I am thinking of a 600va or 650va UPS from Digitus or Dynamix.
Sizing a UPS is like asking how long is a piece of string...
A 600va UPS has a 12v 7ah battery, therefore 12v x 7Ah = 84wh.
My ONT, UFB router, WiFi router, phone Ata and phone uses about 24w.
So by my rough calc is 84wh/24w = 3 hours of run time.
This would be more that enough time based on power outages I have seen in recent years.
Am I on the right track?
Battery laptop would take over from my mains powered desktop during a power outage.
TIA.