When I used the new account to login in after signing out the admin account completely, I was not asked to create a new project like in the video, also not asked to upgrade the account. Could you suggest if this behavior has changed? BTW, my trial account has already been there for half an year.
Hmmm… Given that you’ve had your account for a while, is it maybe possible that it had gotten upgraded already, in the past? You might still have a trial credit amount, even if you have upgraded it.
Or is your trial account maybe already connected as an admin to the Google account you intend to use as the user? If you log into a clean incognito window with just your admin account and try to view that billing account info, what do you see? If you then restart your browser and log into a fresh incognito window with your user account, what does it then show you about the billing account? Do you get full information for the first (admin) view and see an error for the second (user) view?
I hope this helps shed some light on the situation. Please let us know what you find. Thanks!