Not too far upthread I said, as a tip, "let go of setting prep - really let it go."
Why that tip? Because - based on my experience - I think the biggest technical obstacle, which can also be a type of conceptual obstacle, to character=> situation => setting RPGing is the idea that situation and also action resolution outcomes are read off the GM's setting prep. So if you don't have setting prep then you can't read situation and outcomes off it, and so you'll have no option but to overcome that obstacle!
We could then ask, OK, if we let some setting prep back in, but we're still committed to character => situation => setting and so we're still going to avoid deriving situation and outcomes from setting, what is the setting prep for?
Here's one answer: it can help play a type of "coordination" or "indexing" role, in respect of the shared fiction. Eg I often use the World of Greyhawk for this purpose: the maps, and some fairly generic backstory. So when a player wants to have an isolated wizard's tower in the hills as part of their backstory, we can say "OK, that's in the Abor-Alz" - and that means the Elf PC probably comes from Celene.
The index will over time generate some of its own logic - eg if the PCs are at the tower in the Abor-Alz, and want to get back to Hardby, we can look at the map and see that some time is going to pass on that journey. The game system itself will then give us ideas about how to handle that - eg via sheer narration, or taking the opportunity to frame a check or two, etc.
For this to work, the index - ie the map and backstory - needs to be shared at the table.
In my own play, as well as GH I've done this using Middle Earth (in a fantasy adaptation of Marvel Heroic RP), using Washington DC and the east coast of the US (in MHRP), using early mediaeval Britain and Europe more generally (in Prince Valiant), using Soho in London (in Wuthering Heights), and using the emergent star map in Classic Traveller.
While there is a resemblance, here, to the role of maps in (say) classic D&D play, when we're talking about techniques I think it's more helpful to emphasise the difference from that sort of play: to reiterate, that the map is not a device used by the GM to regulate outcomes to somewhat blind action declarations; rather, it is a shared resource used to coordinate narrations of PC backstories, framings of situations, narration of consequences, etc into a coherent whole.
An RPG I know that combines the two different uses of maps is Torchbearer (at least as my group plays it): the dungeon maps work in the classic D&D fashion, whereas the overland/world map plays the indexing/coordination function.
Here's another answer answer about setting prep: it can provide resources for the GM to draw on in framing and narrating consequences - a source of "truths". To reconcile this with character => situation => setting we need framing methods that will get us from character to situation without the GM's prep being an obstacle, and that will get us from situation to setting as part of resolution without the prepared setting and its "truths" being a constraint on how situation unfolds. I think when it's spelled out like this, we can see that it's quite demanding. Burning Wheel doesn't completely satisfy this demand - the GM advice in the Adventure Burner/Codex, for instance, says that sometimes the GM simply has to say 'No, that action <typically a knowledge-type check> can't work because the answer is cordoned off as part of my 'GM's big picture'." The RPG I know that does meet this demanding spec is Apocalypse World.