I keep modem, router, APs, and PCs on UPSs.
On Spectrum coax and their service stays up for nearly all of our outages.
How long it will stay up depends on how big their batteries are, and if they have generators at all locations between you and them.
If you need a server cabinet this big...
... then you can afford just to buy a budget cabinet.
Otherwise, how can you afford the power bill?