That's the default distro configuration more than a systemd issue. It can be changed and 20 minutes for a desktop config is far too high.

Agreed, I'd say it's first on the system that isn't handling exiting/shutdown cleanly, and secondly on the distro config timeout value. I get this quite a bit on some machines (I use Fedora) and it is super annoying. I have yet to find which service is resonsible though as anytime I'm shutting the system down is inherently not a good time for debugging :-)

I have googled this in the past with no success, how do you change the timeout?

See `man system.conf.d` and DefaultTimeoutStopSec. This can also be set per-service with TimeoutStopSec documented in `man systemd.service`.

Too high for a server (yes some of us still use servers), a reboot should be back in a couple of minutes and that’s with crazy long bios posts.