Firebase Admin SDK handle expired access token

I'm using the Firebase Admin SDK with ASP.net Core and because we are using workload identity federation instead of the service account key json file i'm creating my FirebaseApp instance this way:

FirebaseApp.Create(new AppOptions()
{
    Credential = GoogleCredential.FromAccessToken(serviceAccountToken),
    ProjectId = projectNo
})

Where "serviceAccountToken" is a Google Access Token received in a previous step. This works like intended, but the access token i'm using expires after 1 hour.

My problem: I couldn't find a way to update the existing FirebaseApp instance with a new access token. My best approach is to use FirebaseApp.DefaultInstance.Delete() to dispose the current instance and then create a new one, but that seems a bit heavy for just updating the access token.

Is there a better approach?

Update:

My next attempt was simply to assign a new token after the token expired via FirebaseApp.DefaultInstance.Options.Credentials = GoogleCredential.FromAccessToken (newToken), but the new credentials are not taken into account.

After reading through the 'google-api-dotnet-client' source code, I noticed that GoogleCredential.FromAccessToken uses AccessTokenCredentials internally (see github). So I tried to write my own implementation of AccessTokenCredential and implement a refresh function there, unfortunately the interfaces for it are all declared internal. In the end, there is still no good solution.