Yes, you can redirect Users to Google Identity Platform (Google IDP) and return them to Discourse but with customization. However, Google IDP does not provide a hosted login mask that aggregates all the providers. You'll need to build or use a custom login page for this.
These are potential workarounds for the Missing Login Mask.
In your Google Identity Platform settings, ensure you’ve added and configured the additional providers (e.g., Apple, Facebook, or email/password) under the Identity Providers section.
Utilize Firebase Authentication, part of Google's Identity Platform, which offers a customizable UI and supports multiple authentication providers.
Set up a custom authentication system using Firebase to manage user sign-ins and then integrate it with Discourse.
I hope this information is useful in addressing your issue.