Hmm tough question: Xcom enemy unknown/within, dragon age origins/expansions, darkest dungeon. Those I’ve beaten and come back to multiple times and they are still fun.
Runners up include Pokémon lg, Zelda lttp, bg3, slay the spire, mass effect, civ, and stellaris
Looks right in my wheelhouse. Does it have much story to it or a campaign? I’ll have to check the video later