Oh.. any chance you only changed the alias, but you didn't go to Security > Manage how I sign in to update your security contact, is that the case?
If that's the case, do you have a trusted device you can get there now to update?
If not, if you are stuck at the step where it asks for code, look for an option like “Show more verification methods” to see if you have a backup (e.g., a phone number or alternate email).
If you don’t have access to any of the options listed, select “I don’t have any of these.” This will begin the recovery process. As part of that process, Microsoft will let you add new contact information — but only after a 30-day waiting period.
This 30-day delay is intentional. It’s a security safeguard designed to protect users in case someone else tries to hijack their account by changing recovery info. The wait gives the rightful owner time to notice and stop unauthorized changes.
Unfortunately, this policy cannot be bypassed. You can read more about it directly from Microsoft here: