If you delete the other Microsoft account that is associated with the email address you want to use, it should resolve the verification issue when you try to make that email your primary address. However, the speed at which you can delete the account may depend on various factors such as account activity or specific policies in place.
To delete a Microsoft account, you typically need to follow the standard deletion process, which may involve confirming your identity and ensuring that there are no outstanding subscriptions or services linked to that account.
Once the account is deleted, you should be able to add the email address as your primary email without any issues.
References: