How to add user to ALL Google Analytics accounts?

I need to add a user with permissions to all 620 Analytics accounts that I have access to with my main Google account. I am trying to add an e-mail of the type something@developer.gserviceaccount.com to all these accounts so that I can edit and manage them through the Google Analytics API.

I'm talking about these kinds of permissions:

https://support.google.com/analytics/answer/2884495?hl=en

https://support.google.com/analytics/answer/1009702?hl=en

Looking at this article, they say that you can delegate permissions at these levels:

enter image description here

The problem is that I have 620 accounts!

Solution

Figured it out! Instead of a "Service account" as I previously created, now I created an "Installed application" credential. This one opens up a browser window that asks me to authenticate, and then can access all Analytics accounts that my Google user has access to. Like this: enter image description here