UNSUPPORTED - Do not attempt to follow me off this cliff!
It seems I just can’t resist looking for walls to bash my head against, and PiOS Bullseye put up a really big wall with a sign "Bash Head Here → 
"
Aside from only supporting Python3, the biggest issue with using PiOS Bullseye (32-bit) for me was the change in the Pi Camera support to the more universal Video-for-Linux. All my vision experiments used the Python picamera module interface which no longer works in Bullseye.
Recently I discovered a preview release of “picamera2” for Bullseye. I just had to give this a try, and quickly found the install documentation to be out of date resulting in an exception trying to import the new module. The day after reporting the issue the docs were fixed and I can report:
My Pi4 PiOS Bullseye 32-bit testbed can snap pictures, videos, detect and record motion, both with an X preview window or “headless” without needing to pop a window!
I had to completely rebuild the testbed after destroying the X window system, somehow, after installing OpenCV 4.5.5 from sources.
Now that picamera2 is working, I need to install OpenCV again… Find wall - Bash Head Here → 