It depends what you use/need your system for. If it's general/internet/school use and you can stomach borking your system—then Arch is a great way to learn even more. It's best feature, by far, is that you control exactly what goes on to your system. All the other distros (there is an Ubuntu minimal now) include a crapload of stuff you may not need.
The problem with Arch is that you will bork your system, just a matter of when. Not a problem if you have things backed up. You will also spend a lot of time chasing down issues. But you probably know that already. The best thing about Arch is the wiki—even non-Arch folks use it.
If you want a set it and forget it system, then Mint. I've used Mint for years, only recently replacing it with Pop_OS, because it natively supports my newer Nvidia card. Based on Ubuntu/Debian, there will be some differences from Fedora of course. Same with Arch.
Ubuntu is a pain in the ass, I've found. It's the gnome desktop (which Pop_OS has too), which does dodgy things like throw systemctl errors that are known but never fixed.
Desktop, whether Arch or Mint, I like Cinnamon. With Arch you can give yourself any desktop you like, from KDE to Xfce.
I've never used Gentoo or Debian
