Never used RTK, just plain redux. But for me it was always unnecessary ceremony. Most application state is rather simple, once you properly organize it into "real" state and computed values.

I think it vastly depends what you use redux for. If you have very complex local state, that is not always in sync with the server, than it may be the right thing to do. For example something like draw.io.

But just for fetching/mutating server data more or less synchronously (view, edit, save) it feels very unnecessary.