A lot of okay examples below, but honestly the game that really nailed this for me was Breath of the Wild. Ubisoft sort of cursed the genre, and now every game feels the same, but BOTW is a breath of fresh air.

Not similar to the Witcher, but Outer Wilds is a game where you explore a fantastical solar system, uncovering secrets.

One of the best games I have ever played

Dragon's dogma. I actually just finished my first play through and it's really underated.

Death Stranding is a game entirely dedicated to traveling. The whole game is about environmental traversal and exploration. Ymmv but it’s one of my favorite PS4 games. Some people love it and others can’t tolerate it. Read some reviews first before jumping in!

I agree it could be fleshed out more but I believe a lot of things were not finished due to budget. As for pawns actually it fits into the theme of the story. I'm not sure if you have seen all the possible endings of the story but it's basically a story of a never-ending cycle. Either the main character becomes the next god, becomes the next dragon or if the pawn becomes the next you, it feels very impactful and it made me understand why things are like what they designed. The way a Ng+ is started when the main character kills himself is also the first I have seen in a game design. Also the forgery system I have not seen in other games. Handing in forged quest items or keeping forged quest items have various outcomes or more rewards, it's a small thing but really quite brilliant.

I highly recommend Outer Wilds.

Whiterun in Skyrim really holds a special place in my heart. Every time I start a new save file, it feels like I'm coming home whenever I step into the Plains District.

Otherwise I'd totally live in Night City from Cyberpunk 2077 even though it's dystopian af.

I expected Pokemon to be the most common answer but only one other person said it. Pokemon. The answer is Pokemon.

Mass Effects universe.

Stardew valley

My pick too, one of the only games I spent hours and hours out of quests just hanging out, hunting and exploring, absolutely incredible work of art 👌

Still the most gorgeous depictions of nature I’ve ever experienced in a game. It’s 7 years old and still blows every other game out of the water. Every inch of the world is like a painting. I’ve been replaying it recently and it’s insane to me how beautiful it is. GTA 6 is gonna be wild. But even then Red Dead will still be special because of the Wild West setting. The nature and wildlife and weather systems all coming together is just magnificent. Plus the beautiful music. Just unmatched vibes.

Elden rings world really knocked my socks off at every turn. So diverse, surprising and rewarding.

I'm always amazed at how dense they made the world feel, one of the few games where a small nook in the middle of a forest can be an adventure in its own right and rival even some of the bigger set pieces.

The Witcher 3. Velen felt foreboding and dangerous. Novigrad really kind of seemed like a bustling city. Skellige was beautifully empty.

This might be a hot take but atmosphere is the best thing out of Hogwartz Legacy. Walking through the castle is fantastic. Beautiful game

Also Cyberpunk

I think this is a great list but I also really like hollow knights and dark souls atmosphere even if simpler picks

Darkwood FTW. Such an amazing atmosphere and intensity in that game.

BioShock

The original immersive first-person shooter/RPG.

I recommend the remastered version. Still holds up great today.

Edit: I mean Doom is probably the real OG but, BioShock is incredible.

I forced myself to play it every day for a week when it came out and haven’t played it since, but I do plan on giving it another shot here and there. It very much is not ready, but it is in early access. I can definitely see it being a fun game with the bones it has, but I doubt it will ever feel like Hyper Light Drifter in the end. They’re more just games with similar skins. The atmosphere simply is not there, and, with it being a different procedurally generated map each time, I don’t think it ever will be. Again, that doesn’t mean it won’t be a fun game with fun combat. I would wait for the full release, unless you want to get it early to support the devs that brought us HLD and help out with feedback on their discord.

Hyper Light Drifter is audiovisual perfection.

Disasterpeace's soundtrack in particular is flawless in concept and execution. I can never listen to it without being constantly blown away.

Guess I have to play Hyper Light Drifter again… man, did I really want to like hyper light breaker though.

Shadows of doubt, detective sim

Project Zomboid, it's a zombie apocalypse simulator, heavy on the simulator

Dwarf Fortress Adventure Mode, the game generates hundreds if not thousands of years of world lore as it makes your playthrough, npcs have unironic memories/dreams/aspirations/fears etc, and you can do literally anything you can think of

Kingdom Come: Deliverance, heard great things about how fleshed out the world is

And while not very nitty gritty interactable, Disco Elysium's world and characters are incredibly well done

Kingdom Come Deliverance 1 and 2 are good at this.

As far as “living in” a world, only a few walking sims do it for me. I love being able to pick up random items and read random labels. The genre is perfect for VR but nobody has done it to the degree I want, yet. The closest I’ve gotten (and it’s very limited) is Gone Home. Open every drawer, pick up and inspect most things. Not everything—and no working plumbing—but pretty good otherwise.

How about in fallout where you drink out of the toilet instead

Night in the Woods! The rust belt setting is amazingly believable, with lots of little details that don't add anything to the plot and are just there to simulate life in a small town. For example you can explore an abandoned subway stop and visit a pretzel stand just for the heck of it.  

It gives that unique feeling of being a kid strolling around town aimlessly and anoying the people around you with questions. You can have very pointless conversations about basically nothing with a character in a sidestreet or on a roof, but that is because the main character is kind of talking to people in a way that leads to such conversations and fits the themes very well

This is where it started for me, I think. There was no going back after that. It is Nukem’s greatest legacy.

Not exactly "lived in" in the meaning of beauty, but Shadows of Doubt main point is exactly a procedurally generated town where every NPC has scheduling and might play a role in your detective story. So everything feels alive.

I'm surprised nobody has mentioned Sleeping Dogs yet.

Edit: also, can't forget about Shenmue

The game you want is called Yakuza.

You can start with either Yakuza Zero or Yakuza Kiwami. If you're more into detective movies, you could also go for Judgement. It takes place in the exact same city.

Play any one of these, and you will know Kamurocho and the crazy people that lives there better than your own neighborhood.

It is probably the best medieval city I have seen in a video game.

Deus Ex: Mankind Divided

Prague is easily one of the best small open worlds ever made. There are surprises in every room and down every street you care to enter, though it isn't really all that big. Not wide, but dense and deep.

STALKER/METRO, every time immersion comes in, those 2 never dissapoint, from the atmosphere to the tension, stuff is top notch (though AI for STALKER varies from smart unstoppable soldiers to something cs:go bots cannot comprehend)

Journey is also immersive even when it's only a 2 hour ride, the desert felt lonely yet so welcoming same with the other places you pass through.

Prey (2017). Prey Prey Prey fuck this game is amazing. The Talos I station is so densely detailed that it true feels like a real space station. There’s nothing quite like it

Red Dead Redemption 2, no contest.

I will make the comparison to Dead Space, because that's what Prey reminded me most of.

The first level of Dead Space lays on the atmosphere real thick. So much so, in fact, that I didn't want to play past that, because it was very scary. I did keep playing though, and while the tension didn't really let up, the fear actually did. As it turns out, it's a great game, you should play it. So is Prey, which is actually the game I made the comparison to recommend.

The world of horizon zero dawn had me incredibly immersed. The lore and remnats of civilization really helped.

If you haven't played any already I would suggest any Bioware game pre Mass Effect Andromeda. That means the original Mass Effect Trilogy which is my personal favorite gaming Trilogy of all time. Each decision is important and they all carry over to the next game as its one continuous story and it's immetsive as hell, every character is portant and you make a special bond with. The first game is a little rough though, so keep that in mind.

The Dragon Age games are also great if you enjoy some fantasy. Also a great story in each game, but it's not carried over, they're all independent stories in the same world. Companions are great here as well and combat is a little dated in Origins, but gets a lot more streamlined in the other 2. Decisions are also important as there are a slew of endings and possible dialogue choices and lines depending on your character creation.

And lastly the oldest one Knights of the Old Republic. It's a really great Star Wars story, so if you enjoy that universe it's a no brainer. Story is amazing really, with a lot of twists and turns. The gameplay is extremelly dated and may seem uninteresting but once you get the catch of it, you won't even notice how old it feels. Decisions are also somewhat important, even though not as much as in the other 2 recommendations as there are really only 2 paths for the character and 2 endings from what I know. Companions are great here too but they are a lot more underpowered than the main character and the relationships are not as powerful as in ME or DA, as it feels like it is the base of what made the other 2 franchises great.

gothic/risen/elex

Gothic 2.. the best and most immersive RPG ever made.

Red dead redemption 2

If immersion is your main concern, given any thought to playing "immersive Sim" games instead? They're generally more "first person shooter/action games with RPG elements" but their main focus is immersion through atmosphere etc, I mean it's right there in the name.

In that spirit, I could recommend some older games: Deus Ex (cyberpunk first person game) and its sequels, Arx Fatalis (first person RPG set in an underground world), System Shock 2 (sci fi action/stealth/horror first person game), Thief (stealth), Morrowind and Oblivion (open world RPGs), the original Fallout and 2 (isometric view open world RPG).

If you'd prefer newer (but still relatively old) games, you have what seem to be their "updated" versions: The Deus Ex sequels, the Bioshock games (spiritual successors to System Shock), Dishonored (strongly influenced by Thief), Skyrim (sequel to Morrowind and Oblivion), Prey (also in the spirit of System Shock).

You could also give a try to Wasteland 2 (isometric RPG kinda like the original Fallout, and itself sequel to Fallout's original inspiration -though it starts kinda slow and limited in the world you can visit, and opens up later; also 3 came out but I haven't played it) and the Witcher series (3 is the most famous one, and while it's open world sandbox nature may be closer to what you're looking for, I feel that Wicher 1 -an utterly different game, more traditional RPG- is the most immersive of the series).

Lastly, not exactly what you're asking for, but as for games that may not be immersive but are super fun to spend lots of time in and showcase the "feeling you're affecting the world around you" thing perfectly, you have Okami (one of my all time fav games, a Zelda/Metroidvania-like action RPG/adventure game where you go around exorcising cursed zones and rebuilding nature around ancient Japan) and The Saboteour (open world third person shooter where you're liberating Paris from Nazi occupation).

Unironically Genshin Impact. You can enjoy the early to mid game wothout any kind of gacha mechanics

Something different, how about Cloudpunk? It’s not conventionally beautiful, after all it’s a dark and moody cyberpunk city. But it’s very chill and undemanding as a game, more akin to an interactive story really, and extremely photogenic.

Zelda: Breath of the Wild and The Witcher 3: Wild Hunt both qualify.

Some that come to mind:

• A Short Hike
• Stardew Valley
• No Man's Sky
• Slime Rancher
• Outer Wilds
• Botanicula

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And many games like Skyrim, Witcher etc that you can put on Story mode and not worry about difficulty.

Red Dead Redemption 2