I have other thoughts, but these are the most objective ones:
Compared to Fedora and EndeavorOS:
I think that to answer that, we would need to know what about Mint, Pop_OS, Vanilla OS, and Nobara you didn’t like.
As a strictly desktop/personal Linux user, could someone enlighten me: What advantage (if any) does RHEL have over Ubuntu Pro at this point?
Since you have LAN parties in mind, be sure to check this list to know what games are (or are not) well supported by Proton under Linux.
https://www.protondb.com/
Proton is the compatibility layer that allows Seam games developed for Windows to run under Linux. Some games, unfortunately, may have problems that cause you to be left out.