Hi, I'm John! I will help you with this.
Microsoft Q&A is public, and we can only provide information. It is beyond our capability to assist directly with the account or login-related issues.
Microsoft Account Recovery form is currently the only official way to recover your account. You can try it up to twice a day.
If it’s already been a few weeks, you can check this page: "Account recovery unsuccessful" https://support.microsoft.com/account-billing/account-recovery-unsuccessful-dc56c3e3-dff0-4ed5-8edb-60290eea6b53 it includes extra tips from Microsoft that could improve your chances.
Fill out the form as accurately as you can, include any old passwords, subjects of recent emails, or contacts you remember. The more details you provide, the better the chances of recovering your account.
If you have any recurring subscriptions or payments linked to this email, I also recommend contacting your bank or card provider to block those charges until your account is secured.
I know this process can take some time, but this is currently the only way Microsoft can verify ownership without access to the old phone number.
Let me know if you have any further questions or concerns.