You misunderstood my question. How old are those installs? Chances are they're not very old.
Arch-based systems like EndeavourOS are rolling releases with minimal testing. They'll work fine at the start, but errors will accumulate over time. Breakage is not a question of if, but when, and when that happens, Arch assumes you're a savvy user who knows what youre doing and able to fix your stuff. If you aren't (and newcomers to Linux normally fall into that category), you're going to have a bad time.
Whatever the hype around Endeavour or CachyOS is: I wouldn't recommend any of them to Linux newcomers for this very reason. Instead, it's wise to give them a stable Debian-based OS to make themselves comfortable with Linux. Once they have arrived, they may or may not experiment with other flavours of Linux.