My problem is exactly described here:
Then I pass, let’s say, a Google authentication, and get back to callback, it executes
And then goes back to login page where I check if user is already authenticated…
AND IT DOESN’T!
auth()->check() or Auth::check() is False, as Auth::user() or auth()->user() is NULL
And the session is cleared…
So it always tries to login, after previous login success
Probably, your Laravel quickstart tutorial is missing for some steps about saving user logged in in Laravel app