Soto is arguably the best hitter in MLB, right up there with Judge and Ohtani, and the latter two are on the downside of their career. Soto's position this off-season seems similar to Harper's when he signed with the Phillies, about the same age. But Soto's numbers are better than Harper's were entering free agency.
That said, the Mets really needed to make this move, because they're an old team. I think Soto is the third youngest player they have, behind Vientos and the catcher. The only other ones of significance under 30 are the other catcher, Peterson and Megill, who are 28.