Finally have this working. Many thanks to those that have helped along the way.
I have a SATA SSD (500G) that i use for the daily backups. I created a new logical volume on it. Cloned the debian template to this new SSD and created a “backup” app VM whose sole purpose is to be just a storage device.
I have cron setup to launch my script 1m after midnite
1 0 * * * bash /home/user/backuptossd.sh
qvm-shutdown --wait work
qvm-shutdown --wait finance
qvm-shutdown --wait proton-vpn
qvm-backup -y --profile ssdback
qvm-start --skip-if-running work proton-vpn finance
qvm-run --service work qubes.StartApp+chromium
qvm-run --service work qubes.StartApp+thunderbird
qvm-run --service work qubes.StartApp+org.gnome.Nautilus
qvm-run --service finance qubes.StartApp+org.keepassxc.KeePassXC
qvm-run --service finance qubes.StartApp+chromium
I havent implemented this part yet : executing this script on my backup appvm from dom0. I’ll do that after I have 21 days of backups
find /home/user/QubesBackup -iname q* -mtime +21 -delete