Hi,
Did you get any instructions how to enable this preview feature either from official Microsoft docs or from Microsoft employee? If not this feature most likely is private and requires additional steps that you do not have access to. Private features are by invite only so this is the most likely cause of not being able to enable it. You will have to wait until the feature becomes public.
Please "Accept the answer" if the information helped you. This will help us and others in the community as well.