Would these moves have to be approved by both Houses the
President, and the ratified but the states?
The Constitution is involved here.
No. The Constitution wouldn’t stop them. There was no provision for limiting the number of Supreme Court justices, and Congress can add a state. Only morality and thoughts of consequences had prevented political parties from doing it until recently.
Some say that the few “moderate” Democrats would stop it, but there are no more moderates. They defer to the mob. With our education system, foreign import regimes, hiring preferences and divorce/cohabitation paradigms, it was bound to happen eventually.