If there is dynamism, then it means at least some things can change. "A is A," implies that nothing can change. So either dynamism is not universally true, or "A is not always A."
Not at all. A is A is shorthand for a thing is what it is. A is A applies to anything which can be identified and comprehended by means of a concept, an entity, an event, a relationship, or even another concept. A is A in no way implies there is no change.
Change does not mean change from one thing into another. Your precious quarks, do they not move. A quark is a qaurk, but it changes position.
Hank