> With that being said: this Rock 5B seems to draw 15W worst case, which leaves the available area for PoE.

There are additional PoE standards extending up to about 71W at the client device: https://en.wikipedia.org/wiki/Power_over_Ethernet#Standard_i...

802.3at, aka PoE+, can deliver 25W and is not hard to find even on affordable switches.