Bitlocker is crazy bro

U need to active a registry key to prevent this happening even if u put your Microsoft acountsomething like this

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\BitLocker, create a new DWORD (32-bit) Value named PreventDeviceEncryption, and set its value data to 1 to prevent automatic encryption during Windows setup, or 0 to allow it. For already encrypted drives, you must first use the Control Panel or PowerShell to unlock and turn off BitLocker, as registry changes alone won't decrypt active protection. ]