It is my understanding that UI elements can be placed above or below eachother through the hierarchy, I do not understand why these two buttons are staying above all other ui. The two buttons are in a canvas of their own, and then their is a canvas that pops up for each button pressed, but it always appears behind the buttons even when their orders are switched in the hierarchy.
Use vector layout component on canvas or make an empty game object, place buttons in there and change their position assuming you can change their position in your UI