That's what I was thinking too. My home server consumes like 15 W and is silent.
If you get a rack mounted server made for data centers and stick it in a closet so you can't hear it then yes, i guess this approach makes sense.
I use a Mac Mini. When nothing it up, it draws like 7W!
How do you accurately measure how much current a PC is drawing at any given time? Do you have some kind of measurement device inline with the power cord?
You can use "smart" plug such as the Sonoff S31 (flash ESPHome to make it cloud-free).