Well, I did spend a few days finding a modern version of Linux that can run on a Mac mini PPC... Its OS X was outdated so I installed Yellowdog on it, then Debian and now that Debian don't support 32 bits G4 anymore all I found was Void Linux. Plus side: there's so little loading at boot, it start very fast. Downside: I had to install Linux like it's 1995. So I know well Linux is far from perfect... But it has become at least as good as the competition for my uses.