I'm now running
https://github.com/jawsper/motioneyeos/releases/tag/20220119-dev
Linux Dash 5.10.76-v7 #1 SMP Sat Oct 30 12:58:18 UTC 2021 armv7l GNU/Linux
The camera is an Arducam 8MP IMX219.
I once again have the grey screen and "UNABLE TO OPEN VIDEO DEVICE" in the MotionEye web page.
I actually got this hardware to see the camera before I switched to MotionEyeOS, but I also managed to break the setup on the software side, and decided to try the jawsper version rather than dig my hole deeper with Bookworm Lite.
Afraid I have no idea how to troubleshoot this now, since libcamera is apparently not installed.
My wpa_supplicant.conf worked and the Pi Zero 2w is up on my network and reachable by ssh.
BTW how do I change the ssh password? or even enable it?