If the Sox' payroll goes up to, say, $250m for 2025, and Soto takes up about $47m, that's 18.9% of the team's payroll. Contrast that with, say, Steph Curry and the Warriors. According to
Spotrac, Curry takes up 39.7% of Golden State's 2024 payroll. Assume, just to make this easier, that there's 15 guys on the Warriors and 26 on the Red Sox.
Curry: 6.7% of the roster space, 39.7% of the payroll
Soto: 3.8% of the roster space, 18.9% of the payroll
Now how much impact would these guys have? By WAR (or VORP in the case of the NBA). I'm just adding Soto to Boston's 2024 roster just to make it easy.
Curry (2023-24): 4.4 VORP out of GS's 13.2 total VORP, or 33.3%, 39.7% of payroll
Soto (2024): 7.9 bWAR out of Boston's 47.8 total bWAR, or 16.5%, 18.9% of payroll
So it's actually a pretty close comp, I guess, in terms of value, if Soto got this huge deal.