Starter tier not available, 1st app

Google AI Studio Starter Tier publishing is not available for my account.

I am trying to publish my full-stack web app “Mi Diario Metabólico” from Google AI Studio.

My Google Cloud project is:
gen-lang-client-077066****

The project shown in AI Studio is:
Default Gemini Project

I have not published any apps yet.

When I click Publish, AI Studio shows:

“Default Gemini Project”
“No billing setup”

and only offers:
“Set up billing”
“Refresh”

I do NOT want to enable Google Cloud Billing or add a payment method.

According to the current Google AI Studio documentation, the Google Cloud Starter Tier allows eligible users to publish up to 2 full-stack applications without setting up a Google Cloud project or billing account.

Please check why Starter Tier publishing is not being provisioned/enabled for my account and tell me what is required to make the Starter Tier available.

I am not asking to enable paid billing. I want to use the free Starter Tier publishing option