When you wrote about the video locking - do you mean that the image in the camera app freezes and you can't take the video, or you mean that the video locks while playing back the recorded file?
And what camera app are you using?
The camera app freezes on a single image when starting to taking a video. Only way to get un-frozen is to get out of the app and clear it in the recent apps list.
This is when using the camera within an app that can record video or take a photo WITHIN the app using the Android default camera. Yes I can use an alternate camera like Footef camera fine, but not all apps let me load a video or photo, or I need to send a live photo rather than get out and take another photos because then the time has passed.
The build.prop edit did seem to work for a few days, but now it does not. I did verify the entry is still in the build.prop. Even exiting the app, going into Setting and closing the camera, clearing cache, and stopping the app, clearing that cache, and reopening them doesn't resolve it. Even restarting the tablet doesn't get the camera working within the app.
If there was just a way to specify a 3rd party camera as the Android default camera I think this wouldn't be a problem. I haven't found a way. Build.prop entry? Different way within Android?