Doubt Klingberg will have a high cost. He won't be the best RHD available (Severson and probably 1 or 2 more) and might not even be the best offensive defenseman available (Gostisbehere). By the time you'd narrow it down to small enough focus that Klingberg might be an ideal option, there just isn't much value left.

I’d most likely accept this unless we get a better deal, obviously

That top pairing would be the worst defensively in the playoffs.

It wouldn't be the worst that is just ridiculous but they certainly would be risky. But I bet it would be analytically insanely positive. Like for every goal they give up they create 4 or something silly.