It depends on your needs. It’s entirely possible to just format a bunch of disks as xfs and setup some mount points you hand to a union filesystem like mergerfs or whatever. Then you would just hand that to proxmox directly as a storage location. Management can absolutely vary depending how you do this.

At its heart it’s just Debian so it has all those abilities of Debian. The web UI is more tuned to vm/lxc management operations. I don’t really like the default lvm/ext4 but they do that to give access to snapshots.

I personally just imported an existing zfs pool into proxmox and configured it to my liking. I discovered options like directly passing datasets into lxc containers with lxc options like lxc.mount.entry

I recently finished optimizing my proxmox for performance in regards to disk io. It’s modified with things like log2ram, tmpfs in fstab for /tmp and /var/tmp, tcp congestion control set to cubic, a virtual opnsense heavily modified for 10gb performance, a bunch of zfs media datasets migrated to one media dataset and optimized for performance. Just so many tweaks and knobs to turn in proxmox that can increase performance. Folks even mention docker I’ve got it contained in an lxc. My active ram usage for all my services down to 7 gigs and disk io jumping .9 - 8%. That’s crazy but it just works.