This isn't as hard as you might think.
The bitlocker key is stored in the computer on the TPM.
Return the drive to the computer from which it came.
Go to settings (or search for) "manage bitlocker".
It should show your drive, and that bitlocker is on.
Click on "Back up your recovery key".
You can now print out the key and/or save it to a thumb drive.
You can also decrypt the drive in the "Turn off Bitlocker" option.
Windows 11 encrypts the drives by default. You can turn that off or on for any drive you use.
One thing you want to do is to backup the bitlocker key for every drive you have to either paper or to a USB.
I back mine off to an encrypted USB.