Gmail keeps a record of deleted emails for a max of 30 days. If you remember to retrieve the email within the given time frame, you’ll get your emails back.

When you delete an email from Gmail, it goes to the trash folder. And the Trash folder keeps deleting the emails that are 30 days older. All the deleted emails go there whether you inadvertently delete them or knowingly. You can find the trash folder from the right sidebar, open it and look for the emails you want to retrieve. There is no other way to retrieve deleted emails in Gmail.

Also read here - https://www.phonesupportnumbers.com/blog/gmail-account-recovery/