Juan Soto is a better hitter than Freddie Freeman, pretty comfortably, unless you think that Freeman has just found a way to consistently out BABIP him by 80+ points like he has the last two years. Soto has a better K rate, a significantly better walk rate, he hits more home runs, I could go on. Freeman is a better baserunner. Freeman signed his deal going into his age 32 season, and got 6/162. If you're signing Soto as a free agent going into 2025 at his age 26 season, you should expect, based on the above, to pay him significantly more per year than Freeman got, based on production, lack of expected dropoff, and general inflation. So instead of $27/year, you're paying $35/year. And you would assume he wants a longer contract, because all players do. So make it ten years, at $35m/year, and you're looking at $350m.
The last two years combined:
Freeman - .364 BABIP, best in baseball by 13 points among qualified hitters,
Soto - .273, fifteenth worst in baseball