Could you try to see if the issue occurs in Safe Mode? For more info on how to do this, please click on the following link: https://www.samsung.com/uk/support/mobile-devices/how-to-start-my-galaxy-device-in-safe-mode/
If the issue doesn't occur whilst in Safe Mode, it could be that a third-party app is causing the issue. So, if this is the case, please remove your third-party apps one by one until you find the culprit!
As I mentioned in my other post it seems clear that the Camera app is corrupt and as well as not working itself it also stopped the Samsung Internet QR scanner from working.
I have not installed any third party apps for months except yesterday and today for the necessary replacements and I'm sorry but I'm not going through the rigmarole you are suggesting. The Camera app is uninstalled (using ADB) and the third party replacement is its equal, if not better.
Factory resets are a right pain as Smart Switch does not back up emails (at least not the last time I did a reset) and many custom settings are lost. Too much effort.
I was rather hoping that there was a Samsung site that allowed built-in apps to be downloaded.
The Sammobile site is most interesting, but unfortunately the list of apps has every one from Samsung except Camera! The other had nothing of interest.
I rarely use the phone's camera (which is why I don't know when it first went wrong) so I'll stick with the third party app I have downloaded (I use a 'proper' camera normally). As I mentioned elsewhere, with Samsung Camera uninstalled the QR function of Samsung Internet now works!
But many thanks for your interest.