Check Azure AD/Entra ID under the device’s properties, where keys are stored if the machine is joined. If the device is on‑prem AD and Group Policy was configured to back up keys, you’ll find it in the computer object’s msFVE-RecoveryInformation attribute in Active Directory Users and Computers. If the machine was linked to a personal Microsoft account, the key may be available at https://account.microsoft.com/devices. .
If none of these locations have the key, there is no supported way to bypass BitLocker. The drive cannot be unlocked without it. In that case, the only option is to reformat and reinstall the OS.