The APC higher end "Smart-UPS" models might still be good, I've used them for a couple of decades without these sorts of problems, current 750 kVA one bought in 2017, just had to replace the battery at its prompting only a month ago or so (that's normal).

I can also attest their consumer level including the "Back-UPS" models are subpar. Had one bought by a parent arc inside when I was trying to diagnose what was wrong with it.