We have both Tripp-Lite and APC UPSs in our house. These devices are rated according to the wattage they will be handling plus some overhead. I have an APC 2000VA, or 2000 KW rating. Instead of writing Watts like they've done for a century, they now use Volt-Amperes instead. Without going into electrical engineering, Volts times Amperes is Watts, thus the VA!
Anyway, I determined this by adding up the total rated wattage for each of the devices I have that I want to plug into my UPS. With my stack of hard drives, PC and two displays, I'm around 30% based on the graph on the UPS. The extra overhead was accounted for when I also used to plug my Roland LX-17 digital grand piano into the UPS, but that's no longer in this room.
My brother has a Tripp-Lite in the basement for his setup. He got it on sale, otherwise he would've purchased an APC. It works similarly but without all the extra display features on it. His computer use is also a lot less with a PC, small NAS, and two displays. He got away with a 1KW UPS.
UPSs are not infallible. I had an older APC die on me after more than a decade of constant use. All it took was a severe storm to ruin it and it did damage my old PC due to its inability to stop a surge that also killed the UPS too.
If your UPS died, it could be due to the storms zapping something very badly, or it could've been overloaded. There's also the possibility that it was at the tipping point and fell over due to the storms hurting one of the components at an earlier time. The damage was enough to weaken the UPS so that the other power strip you plugged in was one too many that it could have handled fine before. It's hard to tell and please don't perform any forensics on the UPS even though it would be interesting. There are some very dangerous residual voltages inside that are held in various capacitors and inductors.