To get rid of ads, I went under WAN, said 'NO' to connect to DNS server automatically and I used Adguard DNS servers 94.140.14.14 and 94.140.15.15. Unlike Adguard Family DNS, I still seem to have Youtube comments. Under AIProtection & Parental Controls, I blocked adult content on all clients.
I downloaded the Merlin firmware for my router. I might (?) have found an acceptable alternative.