[justinclift]

Interesting thought, thanks. :)

Probably don't want to get a new PoE switch, as I have a decent (fanless, silent) 16 port HP Procurve switch already that's barely utilised.

PoE switches never seem to be silent, and would annoy me. ;)

The other option I've been thinking of, is getting one of those "smart" power control boards + flashing it with Tasmota (https://tasmota.github.io) firmware.

That should work, and allow for using the official RPI4 adapters. :)