The subscription without Copilot only leaves off the extra charge for their Copilot subscription. It does not change their data harvesting tools being built into their applications.
Microsoft makes it very difficult with a constantly moving target to block the Copilot integrations from being installed and collecting your data. They are now pushing for people to use their personal subscriptions on business systems to bypass IT restrictions.
No they do not have copies of every Bitlocker key.
Bitlocker by default creates a 48-bit recovery code that can be used to unlock an encrypted drive. If you run Windows with a personal Microsoft account it offers to backup that code into your Microsoft account in case your system needs recovered. The FBI submitted a supoena to request the code for a person's encrypted drive. Microsoft provided it, as required by law.
Bitlocker does not require that key be created, and you don't have to save it to Microsoft's cloud.
This is just a case of people not knowing how things work and getting surprised when the data they save in someone else's computer is accessed using the legal processes.