in case you didn’t already do something like that, you can have an “app icon” to run your .sh with the following way:
create a file whatever.desktop in the directory: /home/defaultuser/.local/share/applications
In there write the following:
[Desktop Entry]
Type=Application
Exec=sh -c '/home/defaultuser/whatever.sh'
Name=Whatever
Icon=/home/defaultuser/icon-256x256px.png
Comment="no ideas what this line does"
Where in Exec line put where is your (executable) script, Name what will show in the app grid, Icon if you make an icon for your App, this will be, and Comment… well, this I don’t remember why it is there and I don’t know / tried to remove it. If you want to comment something, the ‘#’ works.
Also, if you are interested for different icon, you can choose from here:
Cheers