Pi-hole DHCP server intermittently unable to assign IP addresses until DNS resolver is restarted

If files get too large or if they contain sensitive information, you could share any file output by uploading it via Pi-hole's tricorder, e.g.

cat /var/log/pihole-FTL.log | pihole tricorder

or in your case

grep "dnsmasq-dhcp" /var/log/pihole.log | pihole tricorder

(See also How do I debug my Pi-hole installation? for other ways.)

We'd then need the token to access the files on our servers, where only trusted Pi-hole members can see them, and where they are auto-deleted after 48 hours.

How did you take care of that?

Note that NetworkManager may run and manage its own dnsmasq instance, which may well interfere with Pi-hole's configuration and operation.