Or you unplug your fridge from the wall and plug it into your inverter, with or without battery backup. Or you just leave it plugged into your APC UPS. I think cheaper ones than this US$60 2000W inverter exist: https://www.temu.com/ar/-2000w-inversor-de--con-pantalla-dig...

In the US they cost a lot more, but they still exist; there's a 750-watt unit at Horror Fright for US$70: https://archive.fo/1pzdK