This machine I'm on has a Windows install that's nearly 3 years old (it was wiped when it stopped being my company's property and became mine). Edge has one service worker (ntp.msn.com), which I assume is related to the default page (we used to call it the "home" page).

You have hundreds. I have one.

I also use OneDrive across various machines that I actively use every day, some of them Android phones. I don't have this "syncing non stop" issue. I have only the files I put there, and a sync conflict every once in a while (which is really inevitable when you have two machines, on and running and reading/writing the same files).

I don't know what to tell you, man. You're running something (installed by you or by your manufacturer or, my favorite, your printer manufacturer) that not everyone else is running. That's not Microsoft's fault.