If you haven't seen it, Kevlin Henney's talk about "The Forgotten Art of Structured Programming"[1] is interesting (if somewhat long in the examples later), and somewhat related. It's not specifically about return early (and a case could be made that it should or should not apply specifically to early return), but it is about if, else, return, and how they affect cognitive load when reading code.
1: https://youtu.be/SFv8Wm2HdNM