My utility has frequent sags, flickers lasting less than 1 second. Happens on windy days when lines touch trees. And sadly, no, they won't trim the trees.

I currently use Eaton UPSs on computers and HT gear which seems adequate. But the Aurender N100 streamer in my stereo cant tolerate the short power dips even tho plugged into Eaton UPS. It requires reboot after any power event before it will play music again.
I was recommended Cyberpower but the reviews on A'zon seem a little rough.
I want it to switch to battery very fast like 1mS, and have sine output. I'd like it to last a few years and have user replaceable battery and battery monitoring for preemptive maintenance. 1000w probably the right power.
Appreciate hearing your advice and experiences. Thanks!