If you render the wrong camera you need to make sure the camera cuts track is actually using the selected camera. Right-click on Camera Cuts → Properties and make sure your camera is selected.
Exposure - what you see in the view window doesn’t necessarily match what you will be rendering.
If you have autoexposure on in the view and have it enabled in the project it will always try to show an image. In your camera details section, there are exposure settings there and also in any post-processing volumes, you have set up. If you want absolute control turn off auto exposure and set camera details to manual and min/max exposure to 1. Adjust exposure compensation to what you want.