Not sure what to say then. I run nixos on ~15 different VMs / minipcs, a total of I guess 6 physical machines. Never had to deal with a UPS battery dying, and havent had to do anything to address NUT breaking. I broadcast NUT via synology NAS though, so the only direct client of the UPS status is the NAS. Ive never once had an issue in the ~5 years Ive had it setup like this.