Realistically? I'd suggest you learn to live with it. The rest of the world does! Those factory +2 extensions work very well.
(You've just reminded me that, 'Beauty is in the eye of the beholder.')
By the way, you seem to be, somewhat, cornfused. You cannot use a +2 extension AND a Pearce floor plate, together, at the same time. It's either one or the other.
Did you say, 'the gaping effect'? I've only rarely read a remark like that on this board; and, usually, it refers to the lack of a butt plug in the bottom of the frame.
Here's a couple of pictures of my G-19. As you can see I use both factory +2 extensions, and Pearce floor plates. I like things this way, too. Whenever I reach for the opposite side of my belt I know exactly which magazine I'm grabbing: a 15 or a 17 round magazine.
(I've been shooting a long time; and I can, often, tell by the cadence of my shots just how many rounds I have left.)
Here's a picture of my G-19. It shows both floor plates.
Here's a picture of a G-21 with a butt plug in the frame. It's the only real, 'gap' I know of on a Glock's grip -
You can, by the way, use a butt plug with either magazine setup.