If your (unknown) LE device supports WOL packet wake-up then you can use that option. If the (unknown) device does not .. there is no magic feature for turning boxes on. ESP would be cool, but we've been trying that for years while drunk and still can't get it to work 
RPi4 does not support WOL because the board is completely unpowered when "off" so the Ethernet device is not awake to receive the WOL packets being sent. The exception is when using POE (Power Over Ethernet) as the HAT is both powered and responsible for powering the board (so can turn it on).
