I hadn't heard of dungeon world before, i'll have to check it out! I'm also considering doing a small hack of Blades in the Dark (i'd been meaning to make a planar rpg for a while now, it's such an underrated genre of fantasy) for it, or maybe trying out something like Troika. Thanks for the suggestion!
There actually is a planar fantasy version of Blades in the Dark! It's called SIG: City of Blades and it's actually referenced in an easter egg in the text!
You can check it out here:
https://genesisoflegend.com/products/sig/sig-city-of-blades/
And you can grab it on itch, here:
https://genesisoflegend.itch.io/sig-city-of-blades
Here's Sig running on its own original system pre-BitD
https://genesisoflegend.itch.io/sig-manual-of-the-primes