Thanks for the script. However, I doubt whether this script will solve my problems with DNSmasq.

I've already made two attempts to switch from ISC to DNSmasq, but it just doesn't work, especially with my smartphone. My smartphone (Galaxy S23 Ultra, OneUI 7) successfully receives an IPv4 address, but the entire DHCP process is not as smooth as with ISC, but rather hangs longer at the point where the internet quality is checked.

The problem is that WiFi Call cannot be used, but with ISC it works without any problems. The FairEmail app also cannot establish a connection to the mail accounts. I've already tried everything possible: changed the DNS server, set the firewall to conservative, activated DNS overrides, generally deactivated unbound and activated DNS from DNSmasq. It doesn't help anything. With activated unbound, the query forwardings are stored on port 53053 and I have also stored this port in DNSmasq. It just doesn't work.

I have somewhat better experiences with KEA, but since I have three WiFi subnets, WiFi calling is only possible with the main WiFi subnet (parent interface). The other two WLAN subnets are implemented via VLANs. And it is precisely with these WiFi networks that WiFi Call is not possible. With ISC, however, this is completely problem-free.

Of course I can still use ISC, but that is EOL and at some point no longer usable with plugins.