I think you were basically right about 2022 - the team had a lot of luck with health and so on. Now, it was an excellent FA class and the Red Sox did get a piece of it ... now Story has not been very good (relative to the purchase price) and that has been a problem.
The team needed a lot of plausible maybes to come through (like 2014 and 2015 actually) and they largely haven't. Basically, the positions where most teams get production, the Red Sox have gotten basically nothing ... and the pitching injuries just exacerbated it.