"stable"
This PDM software is not going to be stable. Its a brand new 1.0 product from a company that moves fast and breaks shit. I doubt they went a single day without releasing patches for this thing.

I have a collection of the PDM alpha releases. That was some of the raw-est most-uncooked spaghetti I've ever seen served up by a software company. There is no way they got this thing across the finish line. It's gonna have issues.

That said, this vcenter-like hyper-hypervisor console showed some promise. It provided one brand new capability, hot vmotion between clusters. While the data displayed about clusters and hosts had a janky feel, it was some sort of common interface.
A poor start, but a start nonetheless.

I dunno. It wasn't useful enough for me. I'll look at it again later. I'm slowly working PVE 9 and PBS 4 into my environment, now that they've aged to a .1 rev, and that's got me plenty busy.

EDIT: Should you decide to have a Proxmox Datacenter Manager adventure, you're really going to want to view the stickied threads at their dedicated forum.
https://forum.proxmox.com/forums/datacenter-manager-installation-and-configuration.28/