If your drive is encrypted with Bitlocker, the only place the Bitlocker Recovery key is automatically stored is on the associated Microsoft account on the link below, be sure to check any Microsoft account that may have been used on the PC and also any work or school account that may be linked to the PC.
https://account.microsoft.com/devices/recoverykey
If you are unable to find the Bitlocker Recovery Key on any account that may have been linked to your PC< do you have a backup of your files, or sue a cloud service like OneDrive to sync your files online,.