Hello,
The 30‑day waiting period is a security protection built into Microsoft accounts. When recovery information such as the backup email or phone number is changed, Microsoft delays the update to prevent a hacker from locking out the real owner.
I understand this feels frustrating, especially if someone else changed your recovery email without your permission. But the waiting period is there to protect your account from being taken over permanently.
During these 30 days, Microsoft cannot shorten or remove the waiting time, even through support, because doing so would allow attackers to bypass the protection.