Agree they are "consistent" as in consistently bad. As I've said before, I think the main reason is then inexperience of most of the lineup.
Duran, Rafaela, Abreu, Wong, Casas, Hamilton, and Grissom are all in their first or second seasons in MLB. McGuire and Gonzalez have more seasons than 2, but neither has been a regular. And the same applies to Refsnyder as an outfielder.
O'Neill played 6 seasons for the Cardinals, but most of them were as a backup. He was fantastic 3 years ago with 141 games, OPS .912, and 34 dingers, but has tapered off since then.
So the one bonafide regular in this lineup is Rafael Devers, who is in his 7th straight season as the Sox starting third baseman.