I run two Pi 3b Pi Hole hosts as primary and secondary DNS servers at the house. They've been a fantastic addition to our network and have been running forever. I only have to switch out the micro SD cards every few years.
I only replace the SD's now because one of the OG 8gb cards croaked a long time ago. I guess I could save myself a few bucks and let them run to their logical conclusion. I mean, it's not like it's a tough setup from scratch. 😁
I just have it running as a docker container on a mini PC and I also have tailscale running on it. That way, I can set the Tailscale default DNS to the PiHole's IP and have ad blocking on my phone even when I leave the house. Truly incredible.
I just replaced my pi-hole with Adguard Home running on a NUC I got myself for Christmas. Seems to be fine so far.
It's running on bare metal but I'm tinkering with docker to build a stack of other utilities and will probably move it to docker once I'm more comfortable.
Whatever works! I've played with Adguard also, bu Pi-hole set off a huge ecosystem of open-source ad-blocking/privacy options which continue to grow with time.
I dunno if I'm comfortable enough to jump to Proxmox yet, I'm still learning containers. I did read up on both Proxmox and CoreOS before landing on Ubuntu Server for the NUC. I may move to something more complex eventually, but I wanted something I was already relatively familiar with that I could set and forget.
I had to update mine a couple months ago, complete operating system reinstall because they apparently switched to a different Linux distro and mine was way out of date.