Hmm... this is still "outstanding" but it seems progress have been made recently
I was testing this, and it seemed inter-PVE 9.1 this worked in the SDN setup...... except.. I had to interconnect to a Arista with 1st gen Jericho that doesn't...
hmmm... yeah, getting in a situation where specifying namespaces for some VMs that needs more aggressive pruning (sflow/netflow type data) would've been a perfect solution, as there aren't tags nor other finer grained pruning on PBS available...