Hello Chris! I have been following every step on this thread and I would not say that it's solved for anyone in here. The reason is that there is still a little gap on each side of the desktop to the screen border. It's around 5 millimeters.
Like all the other people around here I am using an AMD graphic card.
I have been using Nvidia for the past 10 years, but during the weekend I've been trying out AMD and since then this border have been impossible to remove.
Everything from setting the overscan to 0% or GPU upscaling active but none of them are helping me getting rid of the border..,
I have been talking directly to AMD support and they asked me if there is a way to change the screen scaling within my monitor. Unfortunately there is not.
Here is an image (bad quality, sorry for that) on how it looks like on one of the sides of the monitor:
I hope there will be a solution for this.