I recently upgraded to Android 9 (Pie) and have an unlocked bootloader. I never applied any DRM fix and the camera works fine. Is DRM still an issue? Could it be the camera quality is reduced even though it's certainly not a green square?
You could test by taking some test photos before and after applying the DRM fix. My guess is the camera DRM was removed for pie. You may have lost image enhancement, but you can easily check this yourself.