For the UPS, I always err on the side of ones that are PFC-compatible, pure sine wave, line interactive. Partly because some of the gear I rack has PFC PSUs, but also because I don't want to be flirting with edge cases in other gear. I've owned 3 such rackmount UPSes, but it doesn't seem to be the default.
The two APC SMX1500RM2U rackmount units that I had at home seemed built very well.
(Currently have two Cyberpower rackmount units, which don't need as much rack depth in my living room, but I kinda expect something industrial-sounding like AMERICAN POWER CONVERSION to be more reliable than cheesy-sounding CYBERpower. :)
I used to swear by APC but they have really gone down hill in the last decade. The first rule of a UPS should be, don't burn down the house. So when buying a new unit this year I went with the brand whose consumer PFC-compatible model didn't have several reviews about it catching fire: Cyberpower.
I had a UPS fail last week, but I have two of them and my servers have dual PSUs plugged into each one. I don’t really need the uptime, but I’m mostly glad I was able to finally justify my unnecessarily high power bill to myself. :)
"Idle" is often measured in the hundreds of watts on enterprise/DC gear.
Newer stuff is sometimes a little better about ramping down at idle, but heck, some server fans will use more power than either of my desktop computers at idle.