I really don't want to be _that_ guy that brings up archlinux, but…
"X is now rootless with the help of systemd-logind, this also means that it must be launched from the same virtual terminal as was used to log in, redirecting stderr also breaks rootless login. […]"
"X is now rootless with the help of systemd-logind, this also means that it must be launched from the same virtual terminal as was used to log in, redirecting stderr also breaks rootless login. […]"
https://www.archlinux.org/news/xorg-server-116-is-now-availa...
This is obviously not a feature of archlinux itself, but an upstream x.org feature.