Hi Permloc,
Thanks for your post! I see your camera will turn on when the device is in your pocket.
Do you have any screen protector or case on your iPhone? If so, do you have this same issue when not using them?
While there is no setting to disable accessing the camera from the lock screen, if absolutely necessary you can disable the camera using Screen Time.
Use Screen Time on your iPhone, iPad, or iPod touch
Now disabling the camera this way, will disable the camera everywhere, meaning you will have to go back into Screen Time and enable when you want to use the camera.
If you would like to see a feature which can easily disable the camera from the lock screen, please submit feedback to Apple:
Product Feedback
Let us know what you find out!
Take care!