But this team was losing when all of the guys you mentioned were healthy. Buxton was playing at an MVP level, and the team was still losing. Cruz was hitting and the team was still losing. We don't know how long Maeda was pitching hurt, but last season was an outlier in his career. Donaldson has been playing his best ball in a long while and the team is still losing. Kepler hasn't replicated his 2019 season, healthy or not. Garver hasn't replicated his 2019 until the last month or so, the team was still losing when he was hitting. Arraez has been excellent...and the team was still losing. Polanco has played his best ball in two years (despite being hurt) and the team is still losing. Sano has been abysmal all season, yet has been healthy most of it. All of those guys have played extended stretches where most, if not all, were in the lineup and they were still losing.
Rosario isn't playing much better than the crop of guys they've run through LF. May has been awful and Clippard hasn't thrown a pitch this season. Have Happ and Shoemaker been effective? No, and they're perfectly healthy as far as we know. Also not mentioned is the bullpen, which has largely been healthy yet completely incapable of holding down a game. So, saying that we're using "stats as a crutch because we don't know what we're looking at" glosses over the fact that healthy players are underperforming. The team is bad. Injuries are a part of it, but its certainly not the primary reason.