Google OAuth on mobile app

I am trying to get login/signup with Google working in my mobile app and I cannot get it work correctly. The signup process works but loads my app in Safari and will not login the user on the mobile app itself.

The credentials save in my DB so no concern there.

I tried setting a deep link to my app in the redirect but the user is still not logged in on the mobile app.

Ive tried using Capactior’s in app browser plugin, everything works except the user is still not logged in on the mobile app.

How do I get this to log the user in on my mobile app?