Anything other than QNAP.
Anything other than QNAP.
Eaton is my recommendation. Look at the 5S1500 (modified sinewave) or 5SC1500. They all work with NUT. I have one of my UPS connected to a Raspberry PI Zero with NUT. And my servers NUT clients are scheduled to shutdown after a 2min outage and my NAS after 4min. I can also monitor the UPS from Home Assistant and receive notifications on my phone each time the UPS goes OB or OL.
I used or it used me for a couple of years. Then while looking for a replacement I found the snap version. I installed it in a fresh Ubuntu VM and it just works.