For me it was Terraria, Satisfactory, Tetris Effect Master Mode, Minecraft with Mekanism mod & CSGO / CS2 (almost 2000 hours in CS alone).
Edit: There are so many answers that I might only reply if I have something interesting to say. I will read all of your answers though. 🙂
Dwarf Fortress. I think I have ten thousand hours in the classic game.
Oxygen Not Included for the same reasons. I really like games where you both design, and are affected by, complex ecosystems