Guys, I believe I found the solution:

https://h30434.www3.hp.com/t5/Gaming-Desktops/Sleep-and-Wake-From-Sleep-Issues/td-p/7371838/page/2

The issue seems to have been the XTU Service (intel extreme utility) - used for overclocking and volt adjustments.I installed this a while ago and thought that I uninstalled it, but it seems the service/driver was still there.

Actually, I believe my original suspicions were correct: it was a background service. This XTU service is used in the omen command center (software used to control lightning, overclocking, other things). I'm guessing a microsoft store update changed some way the service is used and prevents the computer from going to sleep.

Anyways, once I turn off the service, my computer has no problems going to sleep. - edit: it still is running but can still go to sleep. I guess I just have to restart the service or something.

This post was edited by Quant on Aug 13 2020 08:01pm