Hi giordano,
If you want to limit the visibility of the user's dataset, you can create a specific dataset category and assign it to the user role. This way each user can only see the datasets that belong to that category.
Knowage does not allow you to disable upload for users. If you need this functionality, please contact Knowage team https://www.knowage-suite.com/site/about-us/knowage-contact-us/ for professional services.
Thank you
GreetingsAlberto