Creating a SIMPLE animation tool/feature for Affinity Designer is actually VERY easy to do. The devs only need to add codes that will unclick/click the layer(1,2,3) so we will see how the image would look like if animated.
By clicking Play, the layers (1,2,3) will be clicked/unclicked/looped. It's a very simple animation but it's good enough to give us an idea and it's a start.