Just gotten 2x Oak-D S2 PoE cams and have an Orin Nano…..will be testing the connectivity / power-on directly for the direct connection, however have a PoE switch ready for later. From what I understand, you'd still need a form of splitter to run the 2 cat6a cables, one for each cam…to that single port on the Orin….so might as well get yourself a switch.
As to the capabilities of running inference on 6(max) videos, 3 each from every camera…. I'll have to test that…will post back here.
Good luck!