Unlike Windows OS, in macOS, multiple apps can usually be opened at the same time, but there are also some applications that can only open one instance. Because these applications use "singleton mode", a common software design pattern that guarantees that only one instance is running at any time. So when we want to open multiple KiCad ( Launch Multiple KiCad ) at the same time, we can use the following method.

➜  ~ open -n /Applications/KiCad/KiCad.app

AppleScript is a scripting language for automating tasks on macOS systems. Here are the steps to write AppleScript:
1. Go to the "Applications" folder.
2. In the Applications folder, select the Tools folder.
3. In the "Tools folder", Find "Procedure Order Writer" and click it to start it.
5. Click New Document.
6. Enter the following command...

do shell script "open -n /Applications/KiCad/KiCad.app"

6. Save and name it "StartUpKicad" and select "Application".

7. Click on the resulting "StarUpKicad.app" to open a new KiCad.

First, you can use Python's subprocess module to run Terminal commands, as shown below...

import subprocess

subprocess.run(["open", "-n", "/Applications/KiCad/KiCad.app"])

Then use the PyInstaller tool to package the Python code into an App file. Install PyInstaller under Terminal.

➜  ~ pip3 install pyinstaller

Then package the Python code file such as "StartUpKiCad.py" into a macOS App, as shown below...

➜  pyinstaller -w -F StartUpKiCad.py

There will be two directories "build" and "dist" in the folder, open the dist folder and you will see "StartUpKiCad.app".
Click on "StarUpKicad.app" and start a new KiCad.