At this time proxmox backup only backs up VM and Containers - ths guide covers that.
What i didn't realize is the backup job is still defined on the cluster and PBS provides a new storage type that dedupes and managed all the vzdump files created - which is cool.
I decided to run proxmox backup on my Synology NAS where it has more reliable connection to the NAS (i.e. via memory) for doing deduple, garbage collection, prune, verification etc. However the steps here generally remain true.
Once again i used one of Derek Seaman's Awesome Blogs for the basis of this - but with my own tweaks (like using SMB instead of CIFS. As of 9/21 my tweaks are signifcnant, in the original blog it is missing steps to enable encoding acceleration in CTs and VMs.