Storm should absolutely get her own movie. I'm a bit torn on what it should focus on though. I've been a big proponent for adapting Lifedeath 1 & 2. The Windsor-Smith art and deeply personal stories pretty much transcended superhero comics. However, a movie about someone with the coolest powers in comics without those powers is a hard sell. Storm was strong in different ways during that time, but the depowering story needs a particularly skillful writer. Lifedeath would be really well suited to two WatchmenHBO-quality TV episodes on Disney+, maybe as part of a X-men anthology that fleshes out the histories of the characters.
The episode "Whatever It Takes" from The Animated Series had an approach I liked. The Shadow King possessed the boy who essentially is the teenage version of the baby Storm delivered in Lifedeath in order to lure her into a trap. I thought this episode did a lot to give Storm a supporting cast and flesh out the Shadow King as part of her rogues gallery. A "Lifedeath" Disney+ lead up to a "Whatever it Takes" inspired movie would be cool.
Storm also has great stories with Callisto and Yukio where she gets an edge, dons her punk look, and starts considering proactively taking on the X-men's enemies (Storm basically had the development Cyclops got in the 2000s in the 80s). Storm just doesn't have an enemy that really tests her powers (ie gives the movie an excuse to showoff everything she can do). Even the Shadow King is a psionic entity, not a physical threat. If Marvel was smart (which it rarely is) it would assign a brilliant writer to write a Storm comic series right now to start doing that groundwork (supporting cast, rogues gallery, etc).