Hello Jack King,
I’m sorry to hear you are locked out of a brand-new PC.
First, contact Microsoft Support and explain that the newly created account is inaccessible and contains the BitLocker recovery key. Also check every possible key location listed in Microsoft’s https://support.microsoft.com/en-us/windows/security/encryption/find-your-bitlocker-recovery-key. Microsoft Support cannot retrieve or recreate a missing BitLocker key, but Support can review the account-recovery issue.
Please note that this is a user-to-user support forum. Moderators and contributors, including external Microsoft employees, are not allowed to directly interfere with Microsoft product features or access back-end systems. Our role is limited solely to providing technical guidance on reported incidents, requests, or ideas.
Try not to worry too much about the hardware itself. If the account and recovery key cannot be recovered, the PC can still be made usable by reinstalling Windows. This erases the encrypted drive, so only use this option if there is no important data to preserve. Since the PC and account are brand new, the practical loss may be limited, and the computer itself is not permanently locked.