Not addressing Pihole directly, as I don’t have much experience there. But have you maintained a router? Running open source firmware or not, router does require a certain level of maintenance, open source ones arguably more. But that doesn’t make it problematic enough to have a lot of downtime. Given some people runs pihole-like software directly on a router, I’m skeptical the down time there is significant enough to stay away from. I mean having high availability internet at home is hard, but I expect the rate of failure of a router to be similar of magnitude comparing to pihole. If you can’t tolerate the latter, I wonder how you solve the availability issue of the former?