As you are using Bullseye, you may be affected by WARNING: Raspbian October 2021 release bullseye + unbound.
I've only seen this to effect a loop between unbound and Pi-hole so far, but let's check for this nevertheless.
Run from your Pi-hole host machine, what's the output of:
sudo grep -v '#\|^$' -R /etc/unbound/unbound.conf*
Note that Pi-hole's dashboard operates on a rolling time-frame of the last 24 hours.
You defintely have a loop, and that needs to be sorted first.
Depending on the number and chattiness of your devices, you should consider doing something about the rate limit also, either by adjusting it via RATE_LIMIT in pihole-FTL.conf, or by configuring your router to distribute Pi-hole's IPv4 via DHCP instead of using it as your router's upstream (provided your router would support that). If possible, I'd prefer the latter.