If you have a raspberry pi that is always running you can run NUT server on it and that will listen to signals from the UPS. Then install the NUT driver on the Hubitat and have it listen to the NUT server and shutdown. That is how I did it with A Cyberpower UPS at my Mom's house. I use NUT at home also but it's running the server on a Synology NAS.
UPS ->> USB Cable ->> Raspberry Pi with NUT ->> network ->> Hubitat with NUT
