Honestly, I think blunders are in the eye of the beholder. As for the study, you seem best positioned--you tape games, you study them. To make your task easier, consider just looking at 1 run losses, certainly not more than 2 run losses. In 142 games so far, the Sox have 21 losses by 1 or 2 runs--piece of cake.
Based on Kimmi's numbers about Sox baserunning and how overall it is a plus, consider throwing out all of those blunders.
That leaves errors, of which the Sox have a bunch, and those become more interesting when you compare the Sox to the Guardians, who have committed the fewest in the AL this year, 66. We've made 91. Bogie has the most with 16, but the next most is 7, which tells me Bogie has hurt us, but that is not a surprise. The Guardians have given up 31 unearned runs and the Sox 53--pretty significant in my eyes.
Here's a couple more numbers that frankly stunned me. The Sox and Guardians have the two best ERA's in the AL--good for us. However, the Sox pitching (and defense) have given up 584 runs and the Guardians pitching and defense 513 runs. That's a big difference. Indeed, the Yankees are right up there with us despite a decent ERA.
The Guardians vaunted hitting this year actually ranks 4th in the AL in runs scored behind Houston, NY, and Texas. Those 513 runs against, on the other hand, are not only the best in the AL but buy a big margin--our 584 is actually second lowest (second best) in the AL. To me the inescapable conclusion is that the Guardians have far and away the best overall defense--pitching and fielding--in the AL.
Left out, of course, are the mental errors or blunders that don't get into the box scores, and I think those loom large in your view of things. This is especially true because you have said some errors, maybe most of them, are inevitable.
Still, I've just boiled this down to 21 games, which is not a bad place to start.