Well, that was... Fun? The first set of upgrades went perfectly. Then moving to pve 9 I had one host that hit a bunch of AppArmor issues, DKMS issues, brand new unique corosync issues that nobody running proxmox has experienced before if the ddg search is to be believed, and several issues caused by having had podman installed on that host in the past, now that proxmox directly supports pulling in OCI containers and converts them to LXCs. And then all the rest were completely fine.