Other way around. “Moses” apparently came first. It’s basically the last two syllables of “Ramesses” but missing the initial particle saying who (or what) was the cause of the person’s birth. For Ramesses, it’s Ra, obviously. The Semitic peoples took it and applied it to their mostly mythologised forefather.

Since their culture took the meaning of a name seriously - something we’ve started to lose at least in Anglophone countries - you’d expect there’d be a record of that missing particle for Moses, and yet, there doesn’t seem to be one.

This could indicate there there were a lot of -messes all amalgamated into one.

Imagine, if you will, a compilation of stories about the heroic exploits of Celtic men all named Mac-something and eventually a mythos develops around a unified “Mack”, eventually with allegorical and fantastical stories being built up around him. This hasn’t actually happened in Celtic culture as far as I know, but it puts a context on the whole thing.