Had developed something slightly similar (for now primarily used in-house and API is somewhat clunky and unstable): essentially, a wrapper around ProseMirror that makes it easy to use in React, and introduces an additional abstraction that combines schema features and related editor plugins. Thought someone can make it better, and maybe this is that project.
Tangentially, a cool thing would be to unite ProseMirror with Automerge. That’d enable some killer collaborative editors.