I found the solution to this! Unbelievable that I missed this, but maybe I'm not the only one. In the UI configuration there is also a UPS Name field, I somehow thought this is overriden with the config below but it's not. The names need to match, then it works fine.
I have the exact same issues and can't solve it. Did you or anyone else figure it out? Running a DXP2800 here. Besides the UI not showing anything, the shutdown logic does not work as well. Any help would be appreciated!