the DHCP server does not work for me either 
Fresh Docker installation.
I use docker-compose file.
I configured it with bridge networking as per this discussion (which is linked in Github): DHCP with docker-compose and bridge networking
At the beginning I was thinking that problem is with dhcp-helper, but I've exec to pi-hole docker image, installed some tools, and I can see that port 67 is used:
# netstat -apn
udp 0 0 0.0.0.0:67 0.0.0.0:* -
but when I try:
root@8807fb76fae6:/# nmap --script broadcast-dhcp-discover
Starting Nmap 7.80 ( https://nmap.org ) at 2022-09-28 14:58 CEST
WARNING: No targets were specified, so 0 hosts scanned.
Nmap done: 0 IP addresses (0 hosts up) scanned in 10.33 seconds
it gives me nothing. So, my best guess is that its an issue with pi-hole itself
I did run debug and you can see output here: https://tricorder.pi-hole.net/bedfFxAU/