If you need to authenticate your Google account but don't have access to your previous phone, go to the Google Account Recovery page and follow the procedures, which may include answering security questions or entering a recovery email address.

 Here's a more extensive explanation on how to proceed.

How Do I verify my Gmail account without my previous phone?

How can I verify my Gmail account without my old phone?

https://blogulr.com/MelindaBlogs/howdoiverifymygmailaccountwithoutmypreviousphone-134642

https://www.vevioz.com/read-blog/318501