Asus GuestNetworkPro vs NextDNS

Setting: Asus RT-AX86U_PRO on the 3006 branch of AsusWRT_Merlin and the 1.45 CLI of NextDNS

Situation: I've created 2 guest networks (one for iot devices), configured such that they have their own IP subnet/VLAN ID's and are blissfully unaware of anything outside of them. It was then that I discovered that the guest network clients could not resolve names. 

I have worked around this by manually adding the NextDNS settings manually to the configuration for the guest networks, but this isn't optimal (the clients activity in the logs is no longer identified by hostname, etc).  Anyway, the NextDNS CLI is supposed to be making that step unnecessary :-) 

I went and updated to CLI 1.46, but I don't believe this is resolved by it as it was not mentioned in the release notes. I'm reasonably sure that NextDNS wouldn't be counting these lookups as belonging to a paid account (i.e. If the traffic goes over the paid limit, I'll lose the blocking services). 

Am I correct, and if so, what's the right and proper fix for this?

AdvTHANKSance