What does happen when you tap on the camera icon @maeren
i.e
Nothing or does it open and close again etc ?
Try a soft reboot by turning the phone Off and On.
Make sure your phone's software is up to date please.
And check your apps are updated in your Samsung Galaxy Store and Playstore.
I appreciate you've tried clearing your camera cache but also please try this....
- 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 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.
And.....
- Safe Mode > https://www.samsung.com/uk/support/mobile-devices/how-to-start-my-galaxy-device-in-safe-mode/ turns off downloaded apps and themes etc which may highlight an app or theme that's causing conflict.
As a last resort back up and consider a factory reset and a Samsung Service Centre can help.
I wish you all the best. 
@maeren
