Im using a Uctronics Gigabit poe splitter of amazon
I have found you need to connect all to the pi first then connect the cat 5 cable. then after a few seconds it powers up. if you do it the other way no does not seem to work as well. i thing the switch need to sense the current draw.
As for antennas Im using a mobile dualband vhf,uhf antenna for 433 and an 8di 868 grey pole antenna. both mounted atop of my radio mast on a cross beam.
I did try to use a cisco power inserter. but that did not work so i got a cheap poe switch of amazon
the other boards. one is planned for a remote location and the other to be fitted with a uhf beam attached to my el/az rotator. The plan if works. If a balloon is using horus on 433 and lora on 433, then horus gui can control a rotator just like satellite tracking