Phoenix + Flutter: How to get the User ID from Access Token in Pow?

I got stuck at trying to fetch user info from the Pow access token, so I switched to using Guardian ID token through this tutorial: https://www.youtube.com/watch?v=beW3yscX3ww and this repo https://github.com/ElixirMentor/real_deal_api/tree/main

After login, Flutter just gets the user’s account UUID then passes that around between Flutter widgets.