I'm a big fan of FarmRPG. Semi-idle "numbers go up", mostly text + static images game with a lovely community. It has zero ads and, even though it has a paid currency and some very unoptimized ways to spend it, the game is very generous with it (to the point where I've earned the vast majority of my currency by trading resources). It's a bit janky, but fun.
Shattered Pixel Dungeon is free and great fun. It's a roguelike dungeon exploration game, there are many forks of the original Pixel Dungeon but this is my favorite one. Similar to this is Hoplite, a very short (in the free version) turn-based, almost puzzle-like game where you have to get through monster-filled rooms to proceed. Lots of mechanics that you have to learn to use in order to survive.
For more strategy, seconding Polytopia, as well as Unciv (it even has mods!), which is a Civilization-like game.
For a simple but fun gameplay loop, Alto's Adventure and Alto's Odyssey, where you slide your way down various landscapes. The latter especially adds a lot of fun little tweaks onto the original's formula.
I Love Hue and especially I Love Hue 2 are great "arrange the colors properly" games. Hundreds of levels, no nonsense, solid fun.
I got curious enough to look for the source and roped my partner into it by accident. Feel free to read ahead for some vaguely nerdy rambling.
Between my partner and I, we believe we've tracked down to the specific LoRA that was used to generate this image (yes, it's almost certainly AI generated). There's a few very, very similar images floating about, some of which have more obvious artifacts; in this image, one of the bigger signs is the mess of indistinct orange shapes in the bottom right corner. Other images have multiple water levels, varying number of toe beans, etc. According to the LoRA description: "There is a certain chance to draw extra legs." Tremendous sentence. It turns out there's also a similar LoRA for dogs.
There's a video on BiliBili showcasing this wallpaper (you can find it relatively easily with a reverse image search), but we can't see enough of the comments to get information and looking further into that is a bit too much of a hassle. We're still unsure who specifically made it (the video comments do discuss this, but they cut off before we can read any potential answer), only that it was likely made by a Chinese internet user. If someone was curious enough and able to read them, we would be really curious about what the rest of the comments say. Edited to add: the video came out after the Steam upload that OP shared, and that is the earliest instance of this image that we've found as well, so it's certainly possible that is the source (though there are multiple other uploads of the same or slightly modified wallpaper on Steam as well).
Please do note that I don't intend on commenting on the ethics of the generation of these images, only sharing what we've found.