Wow, even more nonsense. That dog doesn't hunt. The Constitution is the compact between the states that all have agreed to, including the supremacy clause. Some states amongst themselves cannot make a side deal to subvert that bargain that all made in direct violation of that same supremacy clause as well as the clause governing the process of amendment. It is a fundamental tenant of legal construction that where the law provides a way to do something it thereby precludes all unmentioned ways to do the same thing.
The constitutional requirement for amending the constitution is an inevitable (not to be evaded) procedural right possessed by we the people. It isn't in the power of some of the states among themselves to agree to waive that process.
What you say re the Supremacy Clause is no doubt correct. So, in the end, this would go to the Supreme Court where it would be voided. IF it goes to a strict constructionist court which is always hanging by a thread. If RBG kicks off or retires, then we MIGHT have a hope that a conservative court would reject this over the next 10 or 15 years. But, if the progs get another sympathetic liberal court that legislates from the bench, they could make this work. I would not count on Constitution or fundamental tenets of legal construction stopping this in a liberal la-la land. That is wishful thinking.