ColinTaylor
Part of the Furniture
This really needs to be your next step.At this point, to prove concept, I may remove the pihole from the equation to see if I can get back to the initial setup working completely. This would beyond a shadow of a doubt now say the pihole is the cause of the problems; and then I can open a support thread and hope for some help there.
Make sure the PiHole's DHCP server is not enabled.