Wow. I’ve just stepped out of the office for a rage break because pipewire shat the bed again. It’s amazing how sound seems to be a solved problem 5 or 10 years ago but now it’s just offal.

That’s not a pipewire problem, that’s a systemctl problem.

Failed to connect to user scope bus via local transport: $DBUS_SESSION_BUS_ADDRESS and $XDG_RUNTIME_DIR not defined

The error means systemctl --user can’t reach your user’s D-Bus session because the required environment variables aren’t set. This typically happens when you’ve switched users via su or sudo rather than logging in directly, because htose don’t initialize a full systemd/PAM session. It could also be that your session wasn’t properly initialized by systemd-logind or a number of other things. Try spawning a proper user session:

sudo machinectl shell your_username@

and try the systemctl command again.

typically happens when you’ve switched users via su or sudo rather than logging in directly,

I wish typical scenarios were the only ones we had – it’d be a trivial solution.

This is a largely unmolested install because I don’t want to be debugging my desktop. If I had a point other than whingeing, here, that would be it: when the default, vanilla, least-tuned setup falls over on the regular, then it’s fundamentally a failure at its “you had one job” task.