Earlier quoted context omitted.
My very simple solution is to use a smart plug and config the mainboard to wake on power.
But then you're draining your RTC battery. I used to have to replace my mother's PC's battery every 1-2 years before I understood she was leaving it unplugged for most of the day and told her to just leave it plugged in all the time.
Might even save that much in idle draw over the lifespan of the battery.