You don’t want to do that since those broadcasts are detectable not to mention that with PoE power levels you will still not be able to broadcast outside of a datacenter also you can’t build an IC that can even take leverage of that power while being hidden in a cable.
All of these taps rely on external transceivers that will either record the traffic for later extraction or exfiltrate it through other means.
Also while PoE has more power it’s also more sensitive to voltage drop over the line which means the tap it self will be detected while normal Ethernet works from -+0.5v to -+2.0v without any issue the voltage range is to allow for voltage drop over longer cables so any drop would be ignored by both end points as they’ll just assume the cable is a few meters longer.
