Struggling with Backend Authentication for Google Sheets API via Auth0 in No-Code Environment

i make a video to explain my problem, on youtube to display subtitile (im french)
https://www.youtube.com/watch?v=1fjqqKZqVrA&ab_channel=tcouet

I’m a beginner in no code, but I’ve put a lot of things in place, I’m stuck on one thing: I’m having a hard time allowing a user to authenticate their Google account with AUth0 as Google wants, my The goal is to do a GET API on the Google Sheet that the user will give me, but for that I need the code (access token). For the moment my page allows a user to connect to their Google account and then retrieve the code in the url, but all this is not done in the backend when I build the workflow, so I have difficulty to compose the flow because I do not have this information live, because when I am in view of my page and I connect, it opens the Google access request, but then necessarily directs to a mandatory redirection page for Google. So this page is in a new tab, outside the current view of my page (backend), so I cannot easily retrieve this code in url but if I can do it a little blindly. But it is complicated for me to continue the flow without being able to use the feedback from the actions because when I launch the action tests I go off the page. I hope I’m clear enough. Do you have a solution to resolve this and so that I can get the feedback in the backend to continue my actions in my workflow. Thanks in advance.

J’ai fait autrement