Greetings,
This is by no means a top priority improvement to Fusion 360, but it's a little weird that it's not incorporated. Currently, there is no way to move your layers around and organize them. Whatever order you create your layers in is the order they are set to with no option to change.
It would be nice to have an option to "send layer to top/bottom" or the ability to click and drag a layer on top or below another in the List UI.
The best available solution currently is to copy everything from one sketch, create a new sketch and paste. It's a solution, but not a great one. The problem is it can take a LOT of time and on top of that you lose extra dimension annotations as well as fixed constraints.
Please consider adding to an upcoming version of Fusion.
Cheers.