Use Account Recovery Page: Go to the Gmail account recovery page (google>) and follow the instructions. You’ll be asked to provide information like the last password you remember, the approximate date when you created your account, or any other details associated with your account. Google will then verify your identity and help you recover your account.

How to Recover Gmail Account without Phone Number?

https://medium.com/@fixxnotworking/how-to-recover-gmail-account-without-phone-number-c2699ee01514