I haven't had any trouble with my UPS's when on generator power, but my 30Kw 1800rpm unit may have a cleaner waveform than the air-cooled units.
I've removed the buzzers from my UPS's, as I don't need them to tell me when the power is out. LOL
I have one equipped with a 50ah AGM battery that powers my CPAP machine, cell and smart-watch chargers, and a bedside lamp so I don't have to run the genset at night when asleep.
It also prevents a power interruption from waking me up at night.
I plan to add another 50ah battery to the one on my network and security equipment to extend the backup time on those as well.