Google Auth for mobile game

Hello, I got backend with already working setup, and I wrote a frontend to get the code from google OAuth2 and my backend change this code to token that I use for auth. The question is how to make OAuth2 authentication for my Unreal ENgine mobile game?
I mean for example I got can get this link:
FString AuthURL = “Sign in - Google Accounts”;
AuthURL += “?client_id=” + ClientID;
AuthURL += “&redirect_uri=” + RedirectURI;
AuthURL += “&response_type=code”;

And then open it in browser for current platform:

FPlatformProcess::LaunchURL(*AuthURL, nullptr, nullptr);

But for frontend I got my redirect_uri and callback function to get “code” from google response, how can I get back to my Unreal ENgine game from external browser with response from google with “code” and how to handle callback function in Unreal Engine?

Hey Did you find anything on this ?

Would like to do the same with AWS Cognito. Did you find the way for the callback? or any kind of documentation?

Any updates here?