Another suggestion: allow Guest VLAN access to whatever IPs come in as DNS server, maybe that's easier than supporting it as configurable. I've just dumped a few DHCP requests in my router (openwrt)...

@TP-Link +1 on this request, same issue. Finally took the time to setup a Pihole instance, updated dhcp settings in the router to provide that IP as DNS and I find my guest network without internet...

I recently purchased an Archer C7 v5 as it seemed like the best option for OpenWRT. One of the unexpected surprises was OneMesh support meaning I'd only have to get a OneMesh range extender instead...