Fix Velop mesh flooding Pi-hole with PTR requests

Since Pi-hole FTL v5.10.1, Web v5.7 and Core v5.5 released Sep 2021, the default TTL for DNS records directly served by Pi-hole is 0 seconds for allowed and 2 seconds for blocked DNS requests:
(Note: TTL for records procured via Conditional Forwarding would be controlled by the target machine.)

Assuming the Velops would honor that TTL for their PTR requests, that would at least allow you to control the frequency of those requests.

I also vaguely recall a report from a user who were able to tackle this by switching DHCP duty from their Velop to Pi-hole. But that's probably not applicable to your setup with Velops operating behind a router.