Per Matt Cerrone, the Red Sox want "a starting pitcher, an outfielder, and two prospects" for Betts. Presumably they mean two top 100 prospects, but that isn't likely. And no team wanting Betts is going to strip mine their roster to accomodate him. But he is a proposal that makes sense. And by "makes sense", also works out on BTV, because that website, if nothing else, is objective.
but how about this:
Cincy gets Betts
Miami gets 3B/INF Jonathan India (BA #51 pre-2019). OF Aristedes Aquino
Boston gets: LHSP Caleb Smith, CF Lewis Brinson, RHP Hunter Greene (BA #57 pre-2019), OF Monte Harrison (BA #71 pre 2018)
Sox get a SP (admittedly on a sell high), defensive whiz for CF, and two top 100 prospects, although an injury kept Harrison off the 2019 list. The Reds get Betts to couple with Bauer for their 2020 title run. The Marlins get a top 100 prospect at a position of need (3B) and a sell-high outfielder.