2 points
For LUKS user set the key; for bitlocker, I believe the key is automatically uploaded to either your Microsoft account or you system admin’s account.
2 points
Sure LUKS will do what you tell it. Bitlocker will do what it wants and just use the TPM unless you jump through a bunch of group policy edits and such. But you are correct, I had forgotten it does give you the option to backup the key to a txt file during the installation or initial encryption process :)