I run it on my oldest pi, a 2011 model C, as it needs almost no grunt.A couple of questions about PiHole if I may.
How long does it take to set up?
I have a Pi 1 Model B, could I use that without too much fettling, or should I get a Pi 4?
Took me a few hours to install as I had other software on there (which I wanted to keep) and needed to fix some dependencies, if it's all that's to go on then with a fresh OS installed I'd say under an hour.
It lives slung on a shelf in the garage and it just chugs on and on...