I assume you test with different storage types? VMWare file format vs. LVM-thin.
Talking about LVM-thin, it is known that first time block allocation is quite slow. My guess is
that this is the cause for the bad result of your benchmark.
This package is part of the "non-free-firmware" debian component. You need to enable that in your apt sources.list.
See https://www.reddit.com/r/debian/comments/11012k4/tip_all_nonfree_firmware_packages_have_moved_to/
PBS has a new, custom round robin database implementation using higher resolutions. We may switch to this new implementation in the next major PVE release, but this is not yet decided...