I believe this is the core of the issue. You are likely using different DNS servers when DoT is off which is why the test result is coming back differently.
Try creating a avahi-daemon.conf.add file with the following contents:
[reflector]
enable-reflector=yes
If you are able to ping your Apple TV from the primary LAN, the above should make it visible for AirPlay. If you can't even so much as ping, then you will likely need to mess with the...
I can’t think of anything technically that would make sense there. The dnsmasq configuration for DoT does not change at all. All that changes is whether the router makes a call dnsmasq locally or to external DNS servers directly.
Keep in mind I believe the reason for the change was that it was reported by some users that changing the setting fixed false negatives from the Network Monitoring features (i.e. WAN showing as Disconnected). Something to keep an eye on. A cached response would make some sense as a culprit.
Check "Wan: Use local caching DNS server as system resolver" on Tools -> Other Settings. Merlin reverted the default for this setting to bypass dnsmasq/stubby on the router. The way DNSFilter is implemented does not impact DNS traffic from the router itself. You can adjust the setting on the...
Does not matter. The router will use the DNS settings (whether connect automatically or manually specified) prior to NTP clock sync. Once NTP is set, stubby starts and the DNS settings are ignored in favor of the DNS Privacy settings.
On DHCP page remove both dns server entries and change advertise router IP to YES. You will likely have to restart the router so all devices pull new leases instead of renew.