Adding script files on launch

I found this workaround in order for GTK 2 Snaps to read theme settings in Plasma. I’m just wondering how I can launch a script that will create a symlink to that file (or check if it exists), then launch the application?

Without symlink:

With symlink:

to be able set such a symlink to the ~/.gtkrc file you can add the personal files interface to your snap and file a store-request to gain read access to that file … then just add a wrapper script to create the symlink (or copy the file) to your snap before launching the app for the first time.