If you are looking "easy" options, keep using Google Apps Script.
Google Apps Script uses JavaScript as programming language and has several services that make it convenient to automate Google apps like Google Slides.
In order to minimize the convertion work, you might create a web app using Google Apps Script to respond to HTTP GET or POST requests that you might do from Python.
If you still insist is using a Python only code, you should "translate" JavaScript code into Python code and replace the calls to services like Slides (SlidesApp) into calls to Google Slides API. This implies that you will have to use Google OAuth 2.
Another option is that you enable the Google Apps Script API (this also requires Google OAuth 2) and call the Google Apps Script functions from Python.
Also you have the option to change your approach, i.e., instead of using Python run Google Apps Script functions using CLASP, but still can't be qualified as easy.