In traditional fairy tales lmao. In Larian's last game, Divinity Original Sin 2, the two best endings were: 1) you die, and 2) you become a soulless husk, the middle ending was, you become a divine but literally nothing was accomplished, the conflict against the big bad evil continues as if nothing happened...except like a lot of people worship you now even though you fixed basically nothing. And the bad ending was you release the big bad evil just because you're a psychopath...for no other reason. At least in BG3, at least with the Dark Urge Swen confirmed we can become ruler of the forgotten realms...which in D&D is like all of the Prime Material Plane....which, yeah, hell yeah, I'll take that. The absolute last thing I want to do is another generic selfless servant of the people ending where my reward is death or zombification. I do not care, all y'all druids and everything else, have fun getting stabbed I am NOT going through another "good" campaign for nothing. And even when there is a fairy tale ending it's just obnoxious generic stuff like yay, you united all the various groups and whatever and here's like a medal or something...no thanks. I'll take something new and different...VERY few games let you have a real satisfying dark/evil ending that isn't designed to make you feel like a loser. Of the few games with multiple endings some have their endings designed as measures of completionism too rather than actual real divergence...there is only one optimal ending, the rest are just there to make you feel bad you didn't do more.
Just being able to have a real fun evil ending that feels good...I will take that.