Hi there! I'm sorry you're going through this, especially with so many important memories tied to your account.
It looks like the one you have tried is the ACSR form which is the account recovery form for Microsoft accounts. You can also find the Microsoft recovery guide for hacked accounts here:
If you follow the guide correctly, you should get to a form different from the ACSR page that will allow you to submit a report/ticket to Microsoft. If you cannot reach the form, you can also visit https://aka.ms/recovermyaccount you should get an email response within 4 hours the latest. The team on the other end will help work through the issue with you.
Note: The form is hosted on the Xbox support site but is available to all Microsoft account holders not just those who use Xbox.
I hope the information helps somehow!