Once I update the archlinux template to where pacman wants to install python 3.11.3, then qrexec will hang for as long as I let it try.
If I restore a backup (~a month ago), then qrexec works until I do a
pacman -Syu --ignore=python, then after than qrexec hangs again.
I ran another experiment, and
pacman -Syu --ignore="python*" does work. That pesky “*” fixes it.