This is a rather simple but perhaps complicated request.
Adguard Home does a good job of blocking devices from reaching certain 'services', such as youtube. Instead of a blanket block, which denies all devices access to a certain 'service', can it be set up in such a way that only certain devices, identified by their mac or ip address on the network, are blocked from certain 'services'? If not, and you're more familiar with OpenWRT, can this be done on the firmware?
Use AdGuards script and the edge build rather than OpenWRT's opkg version. Also you need the 20.02 RC or you need to get full SSL install as you will be lacking the required SSL librarys on 19.07