Re there topics that cannot be treated in literature?

Are there topics that cannot be treated in literature?Are there topics that are more worthy then others?Does an obscene poem by Catullus have anything in common with a tragedy by Euripides?Do you agree with the ancient hierarchy of genres that puts epic and tragedy first and short comic poems last?Is Plato justified in thinking that poets are liars

Focus on one or two of the below texts (whichever works best). Organized arounf a proposition which is able to be argued for or against. Avoid a mere description. Discover and analyze.

Euripides Heracles and other plays (translation by Robin Waterfield; Oxford Worlds Classics 2003)

Plato Symposium (translation by Robin Waterfield; Oxford Worlds Classics 1994)

Catullus The Complete Poems (translation by Guy Lee; Oxfords Worlds Classics 1990)