I’m running one Pi-hole, but not on RPi. One is an LXC container on my Proxmox host, another is on dedicated Dell Wyse thin client box.

Not sure how many services can be hosted in that way and remain useful. But it’s an interesting idea overall! For myself, I could run a Git forge on local PC. Since I’m the only user, and I just keep my scripts there, it is fine not to run 24/7.