not_a_bot1001, you are sincerely amazing. I cannot thank you enough for this writeup!
Fellow weeb Dad and I were chatting about some ways to figure out what might be causing some Win10 slowness that's crept up and he casually suggested "Boot in diagnostic to get rid of all the background noise and see if it's quicker". So, I think--sure thing, sounds simple enough. And well, as we all know... the rest is history :)
Happy Holidays, Merry Thanksgiving, and all that jazz! Hope you have a nice, bug & infinite-loop-free December!