If your lipo has a bms onboard just use it with the ups. That’ll protect it from any charging issues I’d assume. My wife has been using 2x 9ah lipo batteries in her cyberpower ups for almost 3 and half years now. The last rundown I tried was in June and it ran a little over 30 minutes while web browsing running her pc, the modem, and her fish tank pump. It went untill it hit the sla battery cut off which is 10volts I believe. The original battery was about 4yrs old and wouldn’t even run 10 minutes. It would die before the power would be restored. That was at our old house though, our current one doesn’t have brown outs. Occasionally we have power surges.

It’s working as intended, they can’t track you as well, so you have to verify.