Project Nomads (2002)
(Not to be confused with Planet Nomads)
https://en.wikipedia.org/wiki/Project_Nomads
I think this game would be a great fit:
-Post apocalyptic
-Floating islands, you get to fly around on your own island
-Scenic environments (ok it's mostly floating rocks but it has a real mood to it)
-Maybe more questions than answers
It's a fairly low budget game and has the potential to be frustrating at times, but as far as I know frustration is a common element in game dungeon titles :)
Unfortunately no platform seems to be distributing the game, so your best bet is getting it second hand.
