Can't install additional VM with virt-install
It is possible $HOME permissions are too strict. It is not sufficient for the ISO to be readable - each parent directory needs to have 'x' permission too.
ApArmor or SELinux could be denying access to files under $HOME and/or /tmp
Since you're using the privileged libvirtd the recommended approach is to simply keep the ISO images under /var/lib/libvirt/images/ too, alongside the disks.