How can I hide a project from the portal from customers/internal users?

@Vera Valshonok -

In addition to what @John Funk suggested, you can also control project visibility in the Portal UI by the following - Changing Project settings >> Customer Permissions  and change the Channel access to "Restricted"

Afterward, project admins can manage the project permission role assignment to lockdown the project access.  If users are not called out for the specific project(s), then he/she will not see the project at all from the Portal UI.

Hope this also helps.

Best, Joseph Chung Yin