The BitLocker recovery key for your computer was stored in the Microsoft account which was used to install or reinstall Windows on your computer most recently, which may not be the Microsoft account that you are using now.
My MS account shows my device, but doesn't have a Bitlocker Recovery key associated with it??
If Bit locker was turned ON on that device, why is the Recovery Key not there?
Windows for home | Windows 10 | Recovery and backup
This key is usually saved to your Microsoft account, a USB drive, or printed when BitLocker was first enabled. Please try signing in to your Microsoft account on another device and check: https://account.microsoft.com/devices/recoverykey
If the key was saved there, you should be able to unlock your PC.
If you used a work or school account, you may need to contact your organization’s IT administrator.
Unfortunately, if the recovery key is not available, it won’t be possible to access the system because of BitLocker encryption. In this case, the only option is to format the hard drive and reinstall Windows.