Hi Rey,
Is this the documentation you are looking at? Working with different authentication schemes | ArcGIS for Developers
This has worked well for me in the past. Once you have obtained the App Id after registering a new application with ArcGIS Online, you can copy the ID and paste it in your Python script where you are making the GIS object.
import arcgis
from arcgis.gis import gis
gis=GIS("https://arcgis.com", client_id="myAppID")
After running this, a new window should open in your web browser prompting you to log in. Sign in using your enterprise logins, and then copy the OAuth2 approval code. Go back to your Python script, and paste the code in the prompt to finish initializing the GIS object.
You should only need one application code/client_id parameter for all users in your AD that want to sign into ArcGIS Online.
Does this work for you?
Calvin