Google's domains website has posted confirmation this month that it no longer offers new domain registrations, which was acquired by Squarespace.

On September 7, 2023, Squarespace acquired all domain registrations and related customer accounts from Google Domains. Customers and domains will be transitioned over the next few months.

[domains.google...]

On June 15, 2023, Google entered into a definitive agreement with Squarespace, where they intend to purchase all domain registrations and related customer accounts from Google Domains. Now that the transaction between Google and Squarespace has closed, you're a customer of Squarespace.

More information about the move which goes back to June of this year [support.google.com...]