If I wanted to power ESP32-CAM with POE, would I need to step it down?

So I would think that I would have a problem if I simply connected the hot lead coming from the POE Switch to the 5V pin on any microcontroller.

Rather than blow something up, what is the right way to take a single Cat5 cable and A) power a single microcontroller, or B) split that power at the end of the Cat5 cable and deliver power to multiple microcontrollers?

Use one of these (assuming your esp32 module can accept 5V):

UCTRONICS IEEE 802.3af Micro USB Active PoE Splitter Power Over Ethernet 48V to 5V 2.4A for Tablets, Dropcam or Raspberry Pi (48V to 5V 2.4A) https://www.amazon.com/dp/B01MDLUSE7

Or get an esp with POE built in.

Also, unless you force PoE on the port at the switch or with a power injector, it typically has to be negotiated between the switch and the connected device. Some devices ask for the older non-standard 24V passive, others negotiate the 48V 802.3af (12W per device) or 802.3at (25W per device).

Edit: 24V passive PoE is forced PoE at the switch. 802.3af/802.3at is negotiated between the devices. There is 48V passive 802.3af, but it’s typically negotiated.