Hi @Javier19 ,

Follow these steps to Configure the Unified Navigation to display a workspace in the Workspaces menu :

1. Navigate to All > Now Experience Framework > Experiences.
2. Select the application you want to add to the Workspaces menu on the Unified Navigation.
3. In related lists, select the UX Application Category M2Ms tab.
4. Select New in the UX Application Category M2Ms list.
5. Select Workspace in the Experience Category column.
6. On the form, fill in the fields.

   UX Application Category M2M form

   Field	Description
   Experience Category	Category of the experience added to the Unified Navigation. Select Workspace.
   Application	Application that the experience applies to. Global is the default application and applies across the organization.
   UX Application	UX application that you want to add to the Workspaces menu. Select the Workspace you want to display in the Workspaces menu.

7. Select Submit.

Refer to this thread :Workspace is not visible in the All Workspaces und... - ServiceNow Community