Just change the Access of your login module (right column in the CB module settings) from "public" to "guest" (in joomla means logged-out). Then if you need a different login module for logged-in users, duplicate the module, and set Access to "registered" (registered level in joomla means logged-in).

Does that solve your use-case ?

Yes, Joomla permissions and access levels are a very powerful tool, but have a small learning curve.

This tutorial explains in details how they work:
docs.joomla.org/J3.x:Access_Control_List_Tutorial

Great that it solved your use-case, marking thread as solved