On Ubuntu it’s just an option during installation. So far that’s the easiest install I’ve seen.

OpenSUSE supports a graphical install through their software manager, but I found it caused some issues so I ended using the command line. That was actually very easy if you’re not uncomfortable taking a terminal.

On fedora I followed the official docs but their instructions didn’t work, so I had to find some thread on a forum with alternate instructions. It like an hour to get it working.

For sheer ease of use I would definitely stick to Ubuntu since that’s the only distro Steam officially supports. I’ve had a good experience with OpenSUSE though so I’m sticking with it.