You could look into a devices like the Sonoff Basic R4 or Shelly Plus 1 Mini for making a few devices switchable.
But for your PCs and servers, a UPS that does alerts over USB or serial will let you use a script to shutdown in the event of a power outage. Can relay that to other systems on the UPS too. Wake On LAN to get things back online.
You could look into a devices like the Sonoff Basic R4 or Shelly Plus 1 Mini for making a few devices switchable.
But for your PCs and servers, a UPS that does alerts over USB or serial will let you use a script to shutdown in the event of a power outage. Can relay that to other systems on the UPS too. Wake On LAN to get things back online.