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:
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If you must use the computer now, unfortunately you do have to start over, and use a different account for now. Wait 30 days, then link your account back.
How did you reset, did you try to do a clean install via the USB drive? Is the license key asked during the installation process?
Does the computer come with Windows??