I have one suggestion to make
- but I'm nowhere near as experienced as the OP, and I'm surprised there aren't a whole string of replies
I have just rebuilt to factory settings a Lenovo Desktop A540-24ICB (PC is NOT my property)
I then updated it to current Win Update state and installed Reflect so that the owner could do a restore if ever needed.
Of course I set Reflect to run overnight - and it did NOT run as expected
Powercfg on this PC reported sleep states were S0 connected, Hibernate, and Fast Startup
EDIT: Since posting this earlier today, I now find that my suggested Hibernate work around does NOT work
if your system is built with Modern Standby with power S0 Connected Standby
Please read the post by MrSaxobeat on 24th March 2019
reporting a definitive statement by $M$S
"Modern Standby" Energy management. Wake-Up is only possible by pressing the ON-key or by an external server which pushes software updates.
Wake-Up by the Task scheduler (wake timer): Not possible
Wake-Up by Wake-On-LAN: Not possible
Wake-Up by something on the USB-Port: Not possible
Wake-Up by disconnecting/connecting power: Not possible
Disable Modern Standby: Not possible
In brief, Modern Standby systems do not support power on by a scheduled application.
Any visible Power options about wake timers are ineffective (and better hidden - my conclusion)
I can't do full checks, as I will no longer have the PC