In regards to your camera try clearing it's cache via Settings > Apps > Camera > Storage > Clear Cache > Turn the phobe Off and On and then see what happens.
To clear the phone's System Partition Cache Files Section follow this guide.
> Clear Cache Files from the phone's System Partition Section > https://www.samsung.com/uk/support/mobile-devices/how-do-i-clear-the-cache-on-my-device/ You may need to insert your earphones or hook upto a powered On Laptop or use a Tv's USB Port to access the Clear Partition Section. This may help with lag or stutters as this clears the phone of old/unused or broken cache files.There is also a Repair Apps option in the Menu System too.
There is also a diagnostic tool found in your Samsung Members App.
A Samsung Service Centre can assess the phone if necessary.
If I can be of any further help then please don't hesitate. Take care. 😎