Render GameObject1 Render GameObject2 Render GameObject3 ... Render Canvas
When using Screen Space overlay, first all GameObjects in the scene are rendered.The canvas is rendered last.
When using Screen Space Camera, that means the camera treats the canvas like Gameobjects. U can treat it like a plane in 3D world except it is always perpendicular to the camera view direction.
Render GameObject1 Render GameObject2 Render Canvas Render GameObject3
The rendering order is from far to near to the camera.
In your case, you can just
Plane Distance of your canvas settings. Make it smaller, so it is nearer to your camera. Thus make it in front of other GameObjects.