I'm in the process of getting my Home Assistant environment up and running, and decided to run a test: it turns out that my gaming PC (custom 5800X3D/7900XTX build) uses more power just sitting idle, than both of my storage freezers combined.
Background: In addition to some other things, I bought two "Eightree" brand Zigbee-compatible plugs to see how they fare. One is monitoring the power usage of both freezers on a power strip (don't worry, it's a heavy duty strip meant for this), and the other is measuring the usage of my entire desktop setup (including monitors and the HA server itself, a Lenovo M710q).
After monitoring these for a couple days, I decided that I will shut off my PC unless I'm actively using it. It's not a server, but it does have WOL capability, so if I absolutely need to get into it remotely, it won't be an issue.
Pretty fascinating stuff, and now my wife is completely on board as well; she wants to put a plug on her iMac to see what it draws, as she uses it to hold her cross-stitch files and other things.
I have never had what you described happen in my past 15 years of using linux, i hope you find your way around things, linux is dope once you get used to it.
My PC goes down from 70W idle to 2W when suspended. I also have a master slave power strip, that turns of all my peripherals (speakers, lights, audio interface, etc) when the PC drops below 10W so that saves some extra energy.
Windows is gonna Windows. Even if you did track down the issue your one update from a borked system or square one when they alter the setting and relocate it on their own accord.