I\'m quite new in using Rundeck. I have job that should be executing a python file. Just to give you an overview my device has python 3.8.5 and 3.7. Rundeck uses the version 3.7
You can define any interpreter for your scripts (python2, python3, etc) on your scrip steps, just go to your job, on the "Script" step (inline script) or "Script File or URL" step click on the "Advanced" button and add the path of your Python 3.8.5 on "Invocation String" textbox and the ".py" on "Extension" textbox, take a look at this.
I leave a job definition example with this:
nodes
true
031b03b4-220f-4ad0-9c47-3ca47506ba82
INFO
HelloWorldPy
false
true
.py
C:\Users\user\AppData\Local\Programs\Python\Python38\python.exe
031b03b4-220f-4ad0-9c47-3ca47506ba82