Indeed, your logs exhibit that requests are forwarded to your Pi-hole's IP:
/var/log/pihole.log.1:17808:Apr 9 08:54:47 dnsmasq[748]: query[PTR] lb._dns-sd._udp.0.0.168.192.in-addr.arpa from 192.168.0.108
/var/log/pihole.log.1:17809:Apr 9 08:54:47 dnsmasq[748]: forwarded lb._dns-sd._udp.0.0.168.192.in-addr.arpa to 192.168.0.200
However, your debug log shows you are using public upstream servers only:
*** [ DIAGNOSING ]: Setup variables
PIHOLE_DNS_1=8.8.8.8
PIHOLE_DNS_2=8.8.4.4
Yet your logs indicate you may have used your Pi-hole as its own upstream in the past:
*** [ DIAGNOSING ]: contents of /var/log
-rw-r--r-- 1 pihole pihole 8361 Apr 9 22:20 /var/log/pihole-FTL.log
-----tail of pihole-FTL.log------
[2021-04-09 22:08:37.610 757M] New upstream server: 192.168.0.200:53 (2/1024)
When looking at the timestamps, it looks like that this was an issue, if in the past.
On your Pi-hole machine, please run:
pihole restartdns
Once finished, could you check
a) that Pi-hole is not listing its own IP as upstream in its UI
The following command may also help:
grep -n "New upstream" /var/log/pihole-FTL.log
b) whether the logs still would register forwards to Pi-hole's IP after the time of restart?
The following command may help with b)
grep -n "to 192.168.0.200" /var/log/pihole.log