For gaming purposes, I also have to recommend Manjaro purely from how great it handles installing graphics drivers. I wouldn't necessarily recommend it for someone's first Linux install, but once you know the basics in case something breaks it provides a better gaming experience out of the box.
I wouldn't be surprised if Mint and Ubuntu are both in a better state in that regard since I last used them. Last time I used Mint on my gaming rig, the bundled Mint drivers had something funky with them. I don't remember what it was but I do remember I had to reinstall them. This was around Ubuntu's 15.04 I believe?
RHEL comes with a price tag (although I think they now have free developer licenses.)
Also RHEL development moves sloooowly. This is a feature and one of the main reasons to go with RHEL instead of not only unsupported distros but also supported-but-faster-moving distros, kind of like on Windows LTSB (I know to little about both to compare them, but enough to know that in certain organzations the promise that it will stay the way it is and by default only receive security updates is a huge feature.)