What the Sox need to contend is more depth in the bullpen and good relievers who can pitch frequently which is why I think Whitlock has to go to the rotation.
They also need a CFer, really really need a good centerfielder. Duran is not the guy, the Red Sox effectively have three left fielders starting in the outfield right now and that's not good.
Now they really need a catcher as well, actually, they're going to need two. I think Wong/McGuire can be an upgrade for the #2 catching slot over plawecki but they need to replace CV, either by resigning Christian Vasquez or by signing Wilson Contreras. Anything short of those two guys is not good.
What they need next year is effectively this.
CF
RF
DH
1B
C
RP
SP2
I think you can fit 1 or 2 of those holes internally, Hosmer should be fine until Casas is ready and he may be good to go to start the year. I wouldn't mind seeing the Sox make a run at Judge, resign Bogaerts, sign one of Contreras or Vasquez and trade for some pitching. There are some intriguing options on the market for starting pitchers, some ACE caliber guys who might come a little cheaper due to injury and age, if you want to take a chance at these guys bouncing back you could make a run at Kershaw/DeGrom, I also like Nola as well buy he will likely cost more. I'm not opposed to trading for a pitcher, but if you're expecting an ACE caliber guy to come back be prepared to give up 2 of our top 5 prospects +++ Teams are going to want Mayer plus. Now if you go after a guy who has one year left on his contract the cost should be less. Think of the Mookie Betts trade.
The argument in defense of the Sox the last couple years have been being up against the Luxury tax and having a depleted farm system, both those factors are gone this offseason.....so it's going to be interesting to see what they do.