My setup is similar, but I'm also a novice in Proxmox. I have 3 nvme ssd, 2 sata ssd and 2 HDD, crammed in a nice optiplex sff.
I also installed proxmox on the 2 sata ssd as ZFS Raid 1.
The vm's will be running on 2 nvme ssd ZFS Raid 1.
The 2 HDD's will be for slower storage ZFS Raid 1.
I...