If you ask AI if it should just be banned to remove any climate concerns it agrees.

Genshin has some cool tricks like shell texturing for moss. A very good cell shader and custom vertex normals on the characters, making it a lot of work to recreate. Also it runs on mobile so it is heavily optimised, which also takes more time.

I would put Ori 2 on this list since similar to hades it has a destinct artists style and many 3d layers on top.

But the hardest to recreate by far not just visually but movement wise and ai and procedural animation is Rain world. Just look at the naking of it is insane how much custom tech this game has.

Its just pixel art with an orthographic view. The 3d space makes it easier to code and not harder to create art for than any 2d game.