Are you setting something on the UI layer to follow the player? If so, that would be your problem.
Yeah, layers are weird. When using a camera you should see what layer the camera is targeting. This is why that layer has the camera, and no other layers do. You can use this to your advantage by making a new layer and setting all of your UI stuff to that layer.
However, I think you are right, someone should start making GDevelop tutorials soon and maybe it will be me. We’ll see.