I just realised that this is a cross-post / follow up from Plan for installing Pi-Hole on single, tagged VLAN - #5 by clicker.
It might help to know that clicker is originally aiming to have Pi-hole filtering just a single VLAN for IoT devices, configured through a Pepwave Surf SOHO Mk3 router.
Note that jfb has analysed your debug log and confirmed that Pi-hole is up and running - it is your clients that are not using Pi-hole, and that is something that has to be configured in your router.
Regarding the current findings for nslookups forced through Pi-hole's IP:
A time out could be happening if your router would block your DNS traffic or if you'd configured a DNS loop, e.g. if you had DNS forwarding enabled, with Pi-hole again being set as DNS server.
A firewall rule on your router could also explain the failing traceroute from your Mac to Pi-hole on the same subnet.
As @deHakkelaar has also observed, the following two results from your output contradict each other by showing different DNS server IPs on your Mac:
scutil --dns: 10.247.71.249
nslookup: 10.247.71.2
That could be explained by a configuration change.
You wouldn't have changed your VLAN configuration in between those two statements (in order to reestablish Internet connectivity fopr your IoT), would you?
And let me repeat my suggestion from your original thread here:
Though we are happy to help you with anything Pi-hole and also may have hints on general types of configuration, providing advice for specific router settings quite possibly exceeds our knowledge.
You may increase your chances for a quick and more knowledgeable answer if you additonally consult your router’s documentation and/or forums on how to specifically apply DNS related settings.