I'm already running a 3-node Proxmox cluster at home, and currently have a ZFS pool for bulk storage. I'm kind of considering that I could spread my disks across my nodes and use Ceph for that purpose ...

I know you asked about using Proxmox in a production environment (that's not me), buuuut I run Proxmox at home on a single server and up until about 2 months ago I ran a three node Proxmox cluster at ...