Account recovery only requires that you know the trusted number to start the process. Go to iforgot.apple.com and put your email in. It will then ask you for your trusted phone number, this is just to verify. On the next page at the bottom in smaller letters click on "don't have access to my device" Or "don't have access to my trusted number". This will then give you the option to add a new number to use (temporarily). Keep in mind once you regain entry to your account you'll need to update your account with the new trusted number still.
Account recovery can take several days, and in some cases weeks.
After you initially start account recovery it will send you an email within 24 hours advising on how long your wait time will be. Don't worry if you don't get the email or have no access because you can simply go back to iforgot.apple.com and that same information is on the website. It will show you the exact date and time you can regain entry to your account. It will send you either a text or call on the date and time specified. If you don't get the call or text, no worries, quickly go back to iforgot.apple.com and the same directions sent will show on the website.
How to use account recovery when you can’t reset your Apple ID password - Apple Support
