It appears that your customer is facing some challenges with managing their network after outsourcing it to a third-party provider. Although the security and client management seem to be handled well, the customer is now facing difficulties with accessing their data due to the strict policies in place.
The customer's Windows 10 Enterprise 21H2 - Experience Pack 120.2212 is configured with various security measures that limit the user's access to system resources, including encryption via BitLocker, password-protected BIOS, and restricted access to the registry and Group Policy settings.
Given these limitations, it may be challenging to extract data from the computer or modify the existing policy to allow the user to access their data. It may be necessary to consult with the third-party provider to discuss possible solutions or alternative approaches.
It is important to ensure that any changes made to the system do not compromise the security of the network or violate any existing policies. It is recommended to work with a qualified IT professional to address these issues and ensure that all security protocols are maintained.