Hi,
Would suggest that you first figure out the functionalities that you want to configure on portal.
Once you zero down those, you would be able to find the correct role (backend and portal). FYI, once you upload composite role for UI5, you can access both UI5 and WDA based applications.
So if you don't want landing pages look and feel, you can set the worksets, pages and roles in visible status. Set visibility of overview iview to hidden. (Overview iview opens the UI5 based landing page). This will give you portal links that can be accessed on detailed navigation panel.
Not sure if this meets you requirement.
Screenshot attached for your reference.
Regards,
Navya.