So two things about this though.
First, let's say you only get 81 games out of him (so, half a season). Over the last three seasons, here's what he's given you per 162 and per 81 games:
per 162: 111 runs, 34 2b, 45 hr, 97 rbi, .283/.382/.579/.962, 162 ops+
per 81: 56 runs, 17 2b, 23 hr, 49 rbi, .283/.382/.579/.962, 162 ops+
So you're getting 23 homers and a .962 ops for half a season, plus a positive dWAR. In fact, for those 81 games, he's giving you roughly 3 bWAR total. This past season, only ONE regular player gave the Sox more than 2.6 bWAR - Raffy Devers at 3.5. So in just half a season, Trout would give the Sox a player worth more wins than anyone else but Raffy gave them for their entire seasons.
Then you'd have Abreu or Rafaela come in and replace him for the games he's missing, and that player is going to give you something, so maybe you're talking about a total of a 4-4.5 win player with Trout+Rafaela (or whomever). That's pretty nice.
Second, if you rotate DH between Yoshida, Turner (if he's even on the team in 2024), Casas, and Trout, you probably can get more games out of Trout than you otherwise would. So maybe you get 100 games out of him. Maybe 120. And then the value goes even higher.
They desperately need RH power, and there are few better than Trout. Yes it's a $37.1m per year commitment through 2030 (!). Yes that may be rough down the road. But in so many ways he'd be a perfect fit for what this team needs - both from a marketing standpoint (what a splash, that would generate all kinds of fan interest) and from an on-field standpoint.