2010 Toyota Prius JBL + Binize Android Head Unit - Backup Camera Won’t Activate

I’m hoping someone has run into this before.
I have a 2010 Toyota Prius with the factory JBL audio system and factory backup camera. I recently installed a Binize Android head unit (Android 15, MT8163 platform).
The head unit is working well overall:
Powers on normally
Sound works
Steering wheel controls work
CAN bus appears to be communicating
CAN setting currently shows: Toyota → PRIUS_XP01
To retain the factory backup camera, I purchased a Toyota camera adapter that converts the factory camera connector to an RCA plug and connected it to the camera input on the Binize unit.
The problem is that when I shift into Reverse, absolutely nothing happens. The radio does not switch to a camera screen, does not show a black screen, and does not display “No Signal.” It simply stays on whatever screen or app I was already using.
Because of that, I’m wondering if the head unit isn’t receiving the reverse signal at all rather than there being an issue with the camera itself.