the "full faith and credit clause", i.e. article iv, sec. 1 of the u.s. constitution, was written after the constitutions of the states that would eventually sign onto the constitution (clearly), and a long (long) time after the term "state" was being used (c.1300 [1]).
Given that a cursory reading of the wikipedia page on this clause states that"At present, it is widely agreed that this Clause of the Constitution has little impact on a court's choice of law decision," I'm at a loss as to how I'm to interpret your one line response as relates to your argument that U.S. states are not as sovereign as a state such as Germany or China.
idk, maybe you were just bored and threw this out into the universe, to see if it would stick, or something.