It is actually insane that they did this. I literally stopped recommending people use GCP over this - you can't get started easily because you have to use another platform for the domain. Why even use GCP at all?
It was also incredibly sticky with GSuite. Setting up security and everything was a breeze -- DMARC email records, SMTP, etc all magic -- I truly couldn't believe when this was announced. It was incredibly sad and I still feel upset about it a year later.
Porkbun is my go to registrar now. And I switched my email to Migadu.
Google Cloud Domains is still a thing, and you can purchase domains from the console still. The registrar changed to square space, but it didn't really impact Google Cloud's usage.