you can say "υπερβολικά ζεστή" to say too hot. "πάρα πολύ ζεστή" in my opinion is used more to describe something too hot and less to describe something very hot. But it's a bit unclear. You can say "πολύ ζεστή" which word to word translates to "very hot". To emphasise you can say "η σούπα είναι καυτή" which comes from the verb "καίω" that means burn.