Yeah NUT is the package I've been looking at, and looks decently integrated into NixOS just, getting around to configuring it is another time sink.
My 1920R and an unused 15A Dell rackmount (h967n maybe) came with my rack, I've got no reason to have two UPS running nor do I want to replace the batteries in another UPS or have a 15A socket installed in the house just yet. But man it's tempting to piggy-back it off the 1920R for shits and giggles.
Waiting on some parts to arrive from AliExpress - once they arrive I'll be able to decommission one of my servers and have all my services running off one board.