BitLocker was created to protect you from a thief who steals your computer. Someone with physical possession of your computer can tamper with it like no hacker is able to do. Unfortunately, and without intending to do harm, computer users sometimes do things to their computers that tamper with the operating system. When Windows detects this tampering, it locks the computer in a way that only the owner of the computer can unlock.
The person who originally installed Windows on the computer is presumed to be the owner of the computer, so the recovery key is stored in the Microsoft account they used to setup Windows on that computer. Thus, the BitLocker recovery key for your computer was automatically stored in the Microsoft account that you used when you originally setup Windows.
If someone else originally setup Windows on your computer, the BitLocker recovery key is stored in the Microsoft account that they used when they setup Windows.
When Windows is reinstalled, a new BitLocker recovery key is generated, and the old one is cancelled. The new BitLocker recovery key is automatically stored in the Microsoft account that whoever reinstalled Windows used when they reinstalled Windows.
These are the only Microsoft accounts where you will find the correct BitLocker recovery key for your computer. There is nowhere else to find the recovery key, unless a backup copy was made and stored outside the computer.
There are also a few who manage to install Windows without using a Microsoft account, which may be physically possible but wrong. In this case, their computer's BitLocker recovery key was not stored anywhere.
Without the correct BitLocker recovery key, I'm sorry to say that you will never unlock the computer, and there isn't anything that Microsoft or anyone else can do about this. If there was some way to bypass BitLocker encryption, hackers would eventually discover it and BitLocker would be worthless.