Well, I love turn based games, so XCOM, darkest dungeon, slay the spire etc are great.
Also, games by paradox, especially stellaris and crusader kings 3 are amazing. They are a bit hard to understand at first, but get really fun after that.
On android I like dead cells, soul knight and AI dungeon
I have a thing for Slay the Spire too, and another solo card based game I love is Ring of Pain. But Super Hexagon is my comfort game. I like solving chess problems. I'm into point and click adventures expecially if they have German speech. I don't mind a retro first person shooter here and there and other genres.
Honestly? Gacha games like FGO, Another Eden, Ensemble Stars Basic, Yumekuro, Akuneko, etc. I like how the story chapters are usually short and binge-able. Getting new characters/cards I like is fun, and I also use them for extra Japanese reading practice to keep my skills from getting too rusty.