We can fix this one right now, if you like.
Create a new text file in the location ~/.congig/gtk-3.0 and name it gtk.css
Paste the following into it:
.background.csd decoration {
margin: 10px;
}
Refresh your desktop:
Or log out and in ...or... reboot to test the change.
Probably.
Gnome-software... eh...
Recommend using Synaptic Package Manager if you prefer a GUI package manager. It is powerful, informative (Very informative) and versatile.
Is that the 470 proprietary tested?
If so, I recommend @swarfendor437 's advice or... Use the 470 proprietary (NOT tested) or the 510 or up driver.
The 470 proprietary tested version (the one with tested in the name) is known to be Buggy.