I guess it depends on the view of people as to how independent states are. They submit to federalism, this would be one other way.

There could well be a 14th amendment challenge to such a compact. The 14th does demand that every male citizen over 21 gets to vote in any election of the electors of the President, but it doesn’t say that it’s that state’s electors. But it will be argued. The state constitution and statute may have things to say about these matters, I don’t think a compact can supersede a state constitution.