Have a look at this script for example https://github.com/francescor/swarm/blob/main/create_swarm_v... which is the "proxmox" side of cloud-init, that then load an ordinary cloud-init https://github.com/francescor/swarm/blob/main/cloud-init/clo...
... # remove snapd trash - snap remove lxd - snap remove core20 - snap remove snapd - systemctl stop snapd.service - systemctl stop snapd.socket - systemctl stop snapd.seeded.service - systemctl disable snapd.service - systemctl disable snapd.socket - systemctl disable snapd.seeded.service - systemctl stop snapd.service - systemctl stop snapd.socket - systemctl stop snapd.seeded.service - rm -rf /var/cache/snapd/ - apt autoremove --purge snapd -y - rm -rf /root/snap # remove apport trash ...