Best practice is to host 2 PiHole instances, if 1 DNS sinkhole fails you can fallback to another one (Primary & Secondary DNS Server) that way you don’t lose internet access.
Certainly read and try to interpret the documents as best as you can, I suggest going the Docker Compose route for hosting as it’s quite straight forward and a great tool to learn if you want to selfhost other software, fiddle around with 1 DNS sinkhole before you jump head first into getting the second one up though.