Workaround
take backup of the original directory desktop-icons@csoriano
from /usr/share/gnome-shell/extensions/
with below command.
sudo cp -r /usr/share/gnome-shell/extensions/desktop-icons@csoriano /usr/share/gnome-shell/extensions/desktop-icons@csoriano.BAK
Open the file /usr/share/gnome-shell/extensions/desktop-icons@csoriano/prefs.js
with below command.
sudo -H gedit /usr/share/gnome-shell/extensions/desktop-icons@csoriano/prefs.js
find the below content
const ICON_SIZE = { 'small': 48, 'standard': 64, 'large': 96 };
const ICON_WIDTH = { 'small': 108, 'standard': 116, 'large': 116 };
const ICON_HEIGHT = { 'small': 86, 'standard': 102, 'large': 134 };
adjust the sizes with basic things like if you reduce the size 48.. reduce the width and heights also with trails.
In my case
const ICON_SIZE = { 'small': 22, 'standard': 64, 'large': 96 };
const ICON_WIDTH = { 'small': 44, 'standard': 116, 'large': 116 };
const ICON_HEIGHT = { 'small': 44, 'standard': 102, 'large': 134 };

for adjusting the text size for desktop icons follow this Q & A How to customize 19.10 Desktop Icon Font Size
/usr/share/gnome-shell
is maintained by APT, so your fix will be broken after next update of correspondinggnome-shell-extension-desktop-icons
package. – N0rbert Jan 21 '20 at 19:27