Notion Integration

i am currently redirecting to an endpoint of supabase.
Though I am having trouble calling the Notion API with the access token Supabase receives.

On another thread I found this:

This should be available in the session from the onAuthStateChange method, the property is called provider_token , so you can retrieve it like:

supabase.auth.onAuthStateChange((event, session) => {
  const providerToken = session?.provider_token;
})

Not sure how to retrieve this within weweb. Any suggestions?