What about startActivityForResult / Permission Requests and all those stuff that was usually needed in an activity/fragment?

None of that changes much. You still have activities with Compose. You might still use fragments with Compose for a while, particularly when you are migrating an existing fragment-centric app to Compose.

yeah I guess I have to start using it to really stop asking dumb questions 😄

The new activity result library is the integration point for those things and compose