3-D
I’m not sure if this will completely fulfill what you are trying to get at, but I think it might help. I am running dual Pi-hole’s on their own VLAN, with static IP addresses. On the other VLAN’s, I then point the DNS to the IP address of the Pi-hole’s. In the first picture “inter-VLAN routing” is checked, this is the only way for this method to work. You can then adjust the internal firewall rules as needed to block internal access.
I also wouldn’t recommend downgrading your firmware.
-Jeff
