I think there is an arc to be had where characters stop getting solo movies and crystallize into stable positions that don't need constant growth. Let them be supporting characters in regular films and even main characters in big team ups, they just don't need to have their own solo movies.

Honestly though, I'd be happy with a couple movies where there doesn't have to be any huge character movement. An established hero, dealing with a crisis. I feel like part of the "issue" with the MCU is the desire to have heavy plot and heavy character focus in every movie. Some smaller, character driven movies with low stakes, some big plot heavy movies with established heroes just doing what they do best, there's space for these to be included as well imo. And I know there is a medium difference, but there are lots of great comic arcs that give a lot of character growth, but there's also good ones that are just.... the hero does their thing. It's cool yo just see them at their best sometimes I think.