Perhaps you may or may not enjoy Space Asshole Red Faction: Guerilla. It’s a 2009 game that got a solid enough PC port that may run on weaker systems. There’s a remastered version but if you’re aiming for low-spec the original might be a better bet.

Anyway, it’s an open world set on Mars and you go around wreaking havoc and blowing up buildings with ahead-of-its-time physics/destruction mechanics. The combat is more like a shooter and you play with lots of explosives. It’s not a huge map by standards today but is a big enough playground to keep one occupied.

I just finished playing Horizon: Zero Dawn for the second time and it was way more engaging than I remember it being back in 2017. Apparently a lot of reviews ragged on it for “not being Breath of the Wild” which is a lame thing to complain about, even if the game came out at the same time, and they share a lot of thematic elements (like heavily focusing on archery, fighting ancient machines, exploring a beautiful world, etc.).

But it’s a very different game, very narrative heavy, very beautiful, and very well-optimized on PC. The combat is very focused and fun in a good way.

My somewhat controversial suggestion is outward. Low graphical intensity PC game, very open world, and some incredibly unique and polarizing design choices. If your favorite part of breath of the wild was world exploration and korok finding, you may love it! If you like quality of life features though, maybe not.

Things like, you have a world map but no “you are here” marker so need to place yourself with landmarks. You need to drop your backpack to fight effectively and remember where you dropped it, the magic system is based on insomnia with the longer since you slept the more mana you have until you push it too far and just collapse. Really really weird game that I still think about all the time years later.

Baldur’s Gate 3 isn’t exactly open world in the strictest sense, but the maps are so massive that you can get the same sense of wonder and exploration as something like Skyrim or BoTW.

You might really enjoy DayZ. The public servers are pretty brutal, but if you find a comfortable RP server you can settle in and really enjoy exploring the landscape. Once you’re used to the mechanics it’s so smooth.

Stereo headphones or even like monitors make hunting a lot of fun, listening to distant sounds trying to find a deer or boar is a lot of fun. And once you’re used to dealing with zombies and the sthough.l mechanics, crafting and all that, it really opens up.

Plus the ability to expand it with modding is pretty extensive. We’ve got some neat stuff on our own server (though not much pop atm), and I’ve seen others that do some next level stuff like player vampires and werewolves and stuff.

Even just the vanilla game is absolutely gorgeous though. If you like exploring, scavenging, and crafting, especially with friends, it’s kind of perfect.

Conan Exiles has a somewhat similar vibe but a bit clunkier and in a low fantasy setting. It’s also got a lot of D&D roleplay servers.

In all honesty, genshin impact is a pretty reasonable facsimile of that sort of game. It’s really grown into its own, and it’s really fun and absolutely massive

That said, I’d only advise it if you are 100% confident you won’t engage in any of the gacha systems – you can play and enjoy the game with the free characters the game gives you, but once you start engaging with the gacha that can be a really dangerous slippery slope. If that’s something that you could fall prey to, I wouldn’t recommend it. But if you think you can play it without investing any money (or, really, more money than you can afford, I don’t know your financial situation) it’s actually a really great time, and the story’s only gotten better as it’s gone on. There’s definitely some stipulations with it, but it’s worth experiencing if you feel like those are acceptable

Not precisely open world but has the same feeling of exploration, discovery and unlocking, Supraland. Harder puzzles, unlock things that make combat easier. Combat is pretty similar to botw.

Have you looked at “immortals: Fenix rising”?

It has borrowed many elements from botw but with a lot of the “Ubisoft open world formula” on top. I really enjoyed it. The combat is deeper than botw in the traditional sense but I found it responsive and easy to learn. The “shrine” equivalents also had some interesting and unique challenges too.

Others have mentioned Elder Scrolls, but nobody recommended Daggerfall yet, so it’s one of my picks. Yes, the 1996 game, which you can play on Unity for a much, much better experience overall. Since the game is free, you don’t need to pay a thing. Combat won’t feel good, tho.

If you enjoy space games, X3 Albion Prelude might be a good option. It’s “open world” in that you can go anywhere right from the start, but the main gist of the game is to get rich so you can get the capital ships. Ship to ship combat is fine, each ship class has strengths and weaknesses. It has a learning curve and can feel needlessly convoluted at times

Kingdoms of Amalur isn’t really open world, but its combat is awesome. Get the original, non-remastered version, and it should run on your stronger PC, hopefully.

What are the exact specs (CPU, GPU, RAM, SSD yes or no) of your PCs? “Kinda weak” kinda covers an enormous and very subjective spectrum.

Noita is on sale!

Dark souls 1. No other game made exploring the world so exciting. I was checking every single nook and cranny because the game isn’t afraid to give you good gear if you look. The combat can be frustrating but the further you get the easier the game gets. Also definitely follow a build guide if it’s your first ds game.

On the switch you have Skyrim (but I’m assuming you’ve played that)

But also there’s a couple games that could be worth looking into. I have no idea how well they play on the switch or if they would even be your cup of tea, but there’s Dragons Dogma(the first one) and also Outward. Again no idea how they play on switch but they’re both open world rpg type games.

If you’re up for something that is specifically all about exploring, you could try Outer wilds on the switch(this does not have combat FYI) but you get to explore a solar system and unravel a mystery.

Assassin’s Creed 1 and 2. I’ve also heard good things about Morrowind but haven’t played it.

I see a lot of MMOs being recommended, but I find them to be either shallow in combat or predatory unless you are seeking MMO specific things, so I’m going to point at single player/coop stuff.

Bethesda has a large selection of open world games, but I pretty much assume people have played all of them (Elder Scrolls / Fallout games).

If you are okay with going outside of Fantasy, the Far Cry series has some impressive technology in their older titles. Far Cry 2 is a personal favorite, your PC might be able to handle it.

Borderlands series.

The original Dragons Dogma: Dark Arisen holds up. This is probably my best recommendation based on your asks.

Lego Star Wars or the Lego Marvel game.

Fable 1, 2, 3

The Middle Earth Shadow of Mordor / Shadow of War Games were pretty incredible but might be too high-end.

The first Red Dead Redemption might run for you.

Early Dark souls games might run. Maybe 1 or 2.

From here, I would start listing old Star Wars Jedi Knight series games.

I could probably go on, but this is most of the good stuff off the top of my head.

I forgot to add Mass Effect. Great for sci-fi, great leveling, and combat.