If for some reason you don’t like the look of NUT, and you get an APC UPS (and maybe some others?), there is always apcupsd. It will run shell scripts upon certain events, etc. Old, simple, works.

I’ve lived in areas where Comcast stayed up during long outages and areas where it didn’t. Not sure about FTTN, but I don’t think consumer broadband services are required to stay up during an outage like copper phone service is.

Take a look at the “AOOSTAR WTR PRO AMD Ryzen 7 5825u 4 Bay Nas Mini PC”

N100 ain’t it.

Maybe i3-N305… or a mini PC with AMD H-series chip (or similar) configured TDP-down if you are concerned about power usage or fan noise.