I am migrating to the new-ish google auth api based on google.accounts.id and documented here https://developers.google.com/identity/gsi/web/guides/display-button
Using the old API I was able to check if a user was logged in before displaying the login button using gapi.auth2.getAuthInstance().isSignedIn.get().
What is the equivalent with this new google.accounts.id approach?
According to their docs, that method has been removed and it's now up to you to directly manage the state of a user's session state: https://developers.google.com/identity/oauth2/web/guides/migration-to-gis?authuser=1#session_state.
I'm dealing with the same issue as you and found this possible workaround using a Cookie instead to track the user's session state. It might be helpful in your situation: https://stackoverflow.com/a/68855272/8056536