sorry fory my late response...
After having checked the settings pages nothing looked unusual, so becuase I was already spending time to the router I decided to update the firmware to the 3006.102.6.
Immediately after the first boot after the update and even after a reboot, I started having some...
I don't have the log of AdGuard anymore because I've tried to unistall and reinstall it to see if the ports were opened by it or not.
I can confirm that unistalling AGH port 53 and 30000 (the one of the Web UI) were correctly closed.
This is the result of the first command:
iptables -v -S INPUT...