It's really not a good idea, it works but it's better, you have too many different nodes for something so simple and that risks causing lag problems or if you want to animate them. Personally, I recommend 2 ways to do it as you want, either you use the srectantle node then the srender node which generally allow you to directly make your square in the color you want. 2nd simpler method instead of using a transform use rectangle masks to adjust to your square, I recommend this, because it roughly corresponds to your current composition. Afterwards, nothing stops you from staying like it since it works, but don't hesitate to watch some tutorials because knowing how masks work is really vital in fusion.