As far as I know, it’s supposed to be power only. Are you saying the auxiliary USB Type-A port on the Floodlight causes your V4 to hang? I remember @carverofchoice mentioning about powering a Eufy camera + Wyze V2 using a splitter cable here.
Initially, I thought you were trying to power a V4 by removing the main V3 camera sitting on the Floodlight. But even if it powers up, you will lose software functionality of the Floodlight.