Finally got round to loading 22.04.4 on QEMU and juliaup installed fine.
A couple of things that might be useful to look at
lsattr -d /tmp
uname -r
I’m not sure it’d be a great idea to keep using a tmp directory in your user folder, not sure what affect it might have.
At the moment I actually have Pop-OS on my machine, which is made by System76, and is what I thought they would ship their systems with. It’s probably irrelevant.