I need some Advice, dear indieweb...

This is probably way more specific advice than you're looking for, but it might help!

"Flipping the premise"

So take an existing story. Not the story itself, but the broader narrative structure. Take the protagonist/antagonist and their overarching idea, and flip them around

So, instead of Batman and the Joker, you get a completely different story about a morally-complex vigilant with manic-depression taking on a corrupt billionaire who's turned a city into his own playground of destruction. A wizard who wishes to make a better world for those born without magic is just derived from Season of The Legend of Korra. You get the idea, different characters, different world, different narrative altogether, but the bones of the story are a subversion of an established narrative structure

Obvious this works better flipping some stories than other. It's nearly-impossible to do well with story's who's villain is an oppressor figure. It also doesn't work as well when the "antagonist" is a force of nature or the protagonist's own inner conflict, rather than a character. But it's a good way to get novel and subversive story ideas that might inspire you, and you'll likely write morally nuanced stories with this, if that's what you into

In terms of worldbuild, I like to this about an established genre, add some sort of counter-intuitive aesthetic theming(s) to it, and then if I want some extra kick, subvert one of those aesthetics. One sort of "world I built" in my head is set in a quasi-utopian dark fantasy world that's mixing soft apocalypse, dark fantasy, with gothic Catholic imagery, but rather than being base on actual Catholicism, it's a alternate version of biblical lore where rather than God and the Devil, you get a character called Them, who ruled over the Three Kingdoms (Arcana, Gaia, Inferna) before They sacrificed themselves to stop the Four Horsemen from bring on the Rapture, instead They created the "Radient Unrapure" by spilling their own blood, Godblood, which has healing properties, and merging the three kingdoms into one. The worldbuilding contrast soft-apocalypse with dark fantasy and biblical ideas, but subverts the biblical aspects by combining God and the Devil into one omnibenevolent being of both light and dark, reimagining the "sacrificial lamb" idea into a story about Them stopping an age of suffering, and Angels and Demons as Messengers and Cavalry rather than Good VS Evil. You don't ACTUALLY have to subvert anything, but I think that helps. The main takeaway here is "conceptual contrast", or combining disparate ideas into one world

Hope any of this helps!