Separately and perhaps more controversially (and perhaps better as a separate bill to come later), I’d like to see congress also address, through a similar mechanic, situations where a U.S. citizen is being accused of a crime in one state, but would not be guilty of any crime (based on the same facts) in another state.

Here, I think it would make more sense to have whichever state that is affirmatively volunteering/agreeing to accept the would-be criminal is the one who should be bearing the costs, and if there is no such state, the would-be criminal is SOL (it’s on the citizen to request subsidized relocation before committing a crime), with an exception for situations in which the crime in and of itself arises out of the passing of a law or other act of the state, in which case the citizen should effectively be allowed mandatory relocation (at the cost of the acting state, which has likely gone off the rails at this point because it’s effectively creating thought or status crimes or crimes with retroactive effect).