You can put that device in LAN/DNS-Filter and set it to for example to NextDNS ip (account can be made at nextdns.io) and there youtube can be blocked and you need to create a "linked ip" or setup a DDNS address on the router under WAN
I have added my kids school laptops under LAN/DNS-Filter and changed a custom field to one of the nextdns ipv4 server addresses and set that custom i changed to their devices in dns-filter.I'm interested in setting up NextDNS on my AC86U. Can you please provide more information on how to set this up?
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