I’ve always been a bit suprised at how frequently people suggest making alternate trilogies using, for example, one edited original movie plus two new movies compiled from TV series episodes. To me that always felt a bit like putting the cart before the horse - it’s mainly convention and cultural dominance of the format that makes trilogies the de facto release approach. As with my Clone Wars edit, I always felt like the priority should be simply presenting the best content in an appropriately consumable way. If that means a movie within a trilogy, great, but if it means a single movie, or even keeping a show as episodes, fine!
There are definitely good reasons to present a trilogy - which typically features a nested three-act structure focusing on core characters and similar evolving themes - so for example Obi-Wan’s TV show might well work as a third prequel if it does enough to contnue the arcs of Obi-Wan and Anakin that it feels like a direct continuation.
But it’s not necessarily necessary!
Taking Book of Boba Fett as a counterexample to the idea of moviefying a TV show: While I completely agree that it could do with some dropped plots and probably restructuring, I’d still approach it quality-first. The flashbacks are great and roughly movie length, so perhaps they’re a movie, or a couple of episodes. Maybe that content belongs before Mando season one, or as a flashback after Boba is encountered, rolling him into the wider Mando story. And perhaps it was odd to have the two-episode Mando diversion, in which case maybe it’d be better to spread that Mando content throughout a (shorter) series of Boba episodes, so it’s a smaller diversion per episode, and the whole show can behave more like a direct continuation of Mando, with the flashbacks having been already covered?
I’d always be more inclined to keep as much that’s good (world-building isn’t necessarily filler!) as possible, and then structure the presentation around what I have.