@DGrg: This is potentially related to the permissions associated with the Camera app. To check, head to Settings > Apps > Camera > Permissions, and enable the available options here. If the issue persists, head back to Settings > Apps > Camera > Storage > Clear Cache > Clear Data, or open the Camera app > Tap the cog symbol > Reset Settings > Reset. Close the app and reopen it, and allow any permissions at this stage. If you have installed any third party apps or features relating to the Camera app, then try uninstalling them temporarily to see if this helps at all.
@DGrg: Can you try restarting your phone in Safe Mode, as this will disable any third party apps and features, and will help to determine if the issue is stemming from an external source. To enable Safe Mode, press and hold the Power button until the 'Power off' prompt appears on the screen then release > Touch and hold Power off until the 'Safe mode' prompt appears then release > To confirm, tap Safe Mode > With Safe Mode enabled, ensure Airplane Mode is turned off. If you're able to access the Camera without issue, then please restart the phone as you would normally, and delete all third party apps from the device. Sadly it isn't possible to tell which one is the culprit, so a process of elimination will be required. Apologies for any inconvenience this might cause you.