I believe Pihole can be run from a docker container so if you have any hardware lying around that will do. The hardware requirements are extremely light, I believe the minimum RAM requirement is like 512 MB so any one of those should do. Personally, mine is running on a 4 with 8 Gigs of RAM and I have literally never experienced a single issue other than needing to power cycle it once or twice a year.
I believe Pihole can be run from a docker container so if you have any hardware lying around that will do. The hardware requirements are extremely light, I believe the minimum RAM requirement is like 512 MB so any one of those should do. Personally, mine is running on a 4 with 8 Gigs of RAM and I have literally never experienced a single issue other than needing to power cycle it once or twice a year.