Maybe there is some relation with orange man erratic behaviour, canadian pm speech in davos, europe considering to abandon usa cloud and other countries that may follow suit?

Just sayin’…

In proxmox you create a vlan on the physical interface and not on a bridge.

Once the physical port has tagged traffic for all vlan but LAN, leave vmbr0 alone, create the new DMZ vlan in proxmox networking and a new vmbr on that vlan, that’s it.