At this point it feels like a Darling makes a lot of sense for a few reasons. Obviously roster build but you need a kid that will be content with coming off the bench. Given that Darling has two years left, I feel like he's perfect for what St. John's needs with this construction. Be the PG for about 15-18 mins a game your junior year, hit some shots, drive the rim when guys like Jackson, Sellers, Sanon are taking breaks from being on the ball or moved around between the 2 and 3.
Then, he runs point next year (if around) with a lot of talent around him that gets revamped while being a PG in year 2 under Rick Pitino that knows his system...like so many that have been successful under Coach P before.
I like the fit, and to me just makes sense and won't (likely) cost you seven figures that some PGs in the portal that remain are commanding.