An over done synthetic edge is easily remedied, by simply lightly jointing the edge on the corner of the stone, the GS20 in your case. Then re-setting the edge on the stone, it should only take 10 or so laps if you used lite pressure to joint.

It should only take a few minutes to put a new edge on it. The other thing that works well for the GS20, is jointing the edge just before putting it on the GS20, so you have a very straight edge and then the 20 makes it’s own edge bringing the bevels together.

Or stropping on linen, just before the GS20.