Apple ID / Cloud mail recovery

Your Apple ID is signed in iPhone or iPad as what your screen shot says , the rescue mail address can't be opened as you don't knew its password , and Apple ID is exactly same as rescue mail address and the code goes to it .

If the device is in your possession , Better convert secondary authentication account into two factor authentication Two-factor authentication for Apple ID - Apple Support

Get a verification code and sign in with two-factor authentication - Apple Support

Note : you have not mentioned about security answers for three respective questions , the Apple ID password can also be reset using them ( date of birth is essential in upcoming steps ) .

Hello StevenKitigwa,

Thanks for reaching out in Apple Support Communities. We're happy to help.

If you have requested account recovery but don’t have access to the email account the notice was sent to, you will want to reach out to Apple Support. They will be able to provide you with the next steps. To contact support, go to Get Support.

Let us know anytime you have questions.

Take care!