Google Offline Access from API Workflow?

I guess another way to state the question is, how do I make a user the current user in the context of a Bubble API endpoint workflow?

EDIT: I think I can distill this down to a question about offline access to Google API’s from an API workflow. I’ve updated the title of this thread accordingly.

I also saw this topic but am still foggy on how to authenticate with Google for offline. When my Bubble endpoint is hit, I find the relevant user, but it’s unclear how to proceed in order to access their Google data.