Hi,
I have setup PVE with CIDR (10.0.1.10/22) and gateway of 10.0.0.1 on vmbr0, and running a Opnsense with vmbr0 as LAN with the same CIDR (10.0.0.1/22) size.
When connecting a laptop to the physical lan, DHCP configed my subnet mask as 255.255.252.0. I can access Opnsense web GUI with this...