I don’t think the lineup matter much on 2018 vs 2019. In fact, the 2019 Red Sox outscored the 2018 team 901 to 876.
Even if you took Betts off that team, it’s still a good lineup.
The rotation, OTOH, has a bit much going on with injuries, ineffectiveness, and a complete lack of depth. The bullpen has some good pitchers, but could use improvement as well. Especially since having no starter depth exploded their workload...