camera green bubble popping up when im not on the app

Now I don't know what you downloaded from the internet. But iOS is pretty secure, so you can hardly download anything that can spy on or damage your iPhone.

You can always get an overview of the apps that have access to your camera, and remove access here:

Settings > Privacy & Security > Camera

If there is something you don't recognize on the list, disable it - and possibly delete the app afterwards. You can also check which apps are using your camera when you see the green indicator. Pull down the Control Center and tap at the top.

No, the Camera app cannot be disabled. Or, you can remove the camera with Screen Time restrictions, but then you can't take pictures. I wouldn't worry as long as it's just the camera app. As I said, iOS is pretty secure, and no apps or websites have access to your camera unless you give them permission.