Hi @Dodo-pilote, sorry to hear about this.
Have you tried clearing data for the camera app? This will reset all settings for the camera app which might do the trick. To do this, find and tap Settings > Apps & notifications > Show all XX apps > Camera > Storage > Clear data.
Another thing that you can try is to reboot your phone in safe mode to see if the behaviour of the camera app persists there. All apps downloaded from Play Store is temporarily deactivated while in safe mode and by doing this you can see if this behaviour is caused by a downloaded app. For more information on safe mode and how to use it, click here.
If the behaviour of the camera app persists after clearing data for the app and in safe mode you might need to repair the software using a computer and Xperia Companion. Keep in mind though that a software repair will erase all user data from the phone, so make sure to do a backup of your user data before the repair.
If none of these measures manages to improve the functionality of the camera app, I am afraid that the only thing left to do is to get in contact with your local support team in order to have your phone sent to an authorized service center to be examined and possibly repaired. If you have any questions regarding the service such as routines, warranty and consumer laws, these kind of questions are best answered by your local support team as well.
Try these measures and let me know how it goes!
