I actually agree that this situation would likely see Democrats start pushing for some various things to game the system, like splitting up California or trying to admit Puerto Rico as a state, for transparently partisan reasons.
Yes, however you cut it, there would be a growing movement to "gerrymander" the states at the left's next opportunity. During a Dem wave midterm year, they could also propose state constitutional amendments by initiative to bind state electors to the NPV winner in any R-leaning swing states that have the initiative (MI, AZ, OH, and FL do, which would have been enough EV to flip the 2016 result). The constitutional issues only come into play when multiple states enter a binding compact with each other. An individual state can assign its electors however it likes.
I suppose the most obvious strategy would be to mass-admit all of the offshore US territories as states the next time they have a trifecta. All except American Samoa (as Mormon as Idaho) should reliably elect Dems.
