DNSFilter should make a hardware device that can be plugged into a network with a static IP, configured as the DNS server, and offer DNS relay. A GUI configuration option would be great to configure relaying DNS to DNSFilter so that LAN IPs can be recorded. Ability to work across multiple VLANs would be ideal. This shouldn't be incredibly expensive as a small Pi could probably accomplish this. Supporting DoT back to DNSFilter would be an added benefit.