It’s worth recalling that Platonic realism is idealism in a manner of speaking. Nominalism takes naive perception of reality for what it is. Reality’s etymology is from real. The etymology of real is matter or thing. Reality simply means then, being, in contrast to non-being. Platonic realism has a world-spirit providing structure for everything that exists from a realm of forms. It is as if God ordered the Intelligence to provide structure and form for everything. An example might be the design of parameters of the Universe that are constants- fine tuned constants, that enabled molecules and atomic structure to exist in standard forms. Berkelyan ideaism differs from Hegel’s- it has a more existentialist sense about it. There is no ‘outside world’ Humans exist in-the-Universe and interpret the forces encountered in similar ways. People interpret light-waves of the electro-magnetic spectrum as colors, shapes, motion etc. Marx’s ideas are so silly regarding anything besides sociological observations, that they have paltry value metaphysics, physics or whatever. Dialectic-trielectic (CS Pierce)-ideas are synthetic constructions from numerous sources sometimes. etc.