calling qualified developers
For the sake of someone that might be able to take this on, you need to be much more specific about what exactly you want running. You can’t just write things like OnePlus. You need too explicitly spec out concrete phone models. I suspect the hardware acquisition costs would exceed the bounty.
When one opens a camera application (like millipixels), the screen should show what the camera points at and capturing color photo and video of that content should be possible. It should run in a stable manner (meaning no anticipated crashes) and the required changes should be accepted into the postmarketOS edge branch.
As for devices, please refer to the linked wiki-page. It names one Shift device and one OnePlus device (and a variant of it). If only one device were to be chosen, it should be Shift.
I understand your concern about cost - maybe the company could be bothered to sponsor a device for this development.
