Thanks for the feedback! I'm quite new so I'm not really sure how to fix that but I will have a look
For the Canvas, use a CanvasScaler with "Scale with screen size" UI scale mode (not "Constant pixel size").For the sprites, a simple solution is to adapt the camera Projection/Size (orthographicSize) to fit the with of the world.
camera.orthographicSize = MyWordWidth / camera.aspect
Thanks, I will be sure to use this for next time