The above is all well and good, but the numbers are the numbers.
As it relates to just the 4 categories ( and there are a myriad of other categories that weren't including. But as it relates to % of headers won, tacked won, pass accuracy and long pass accuracy. John Stones shows a distinct superiority. This might be function not playing so few games, agreed.
But the numbers are simply saying what the numbers are.
Let's take your example for a second, you said Bournemouth were playing vthe long ball and winning headers? Well John wind 65% of his headers same as Larporte. So we can't assume it would have been any better if Laporte had been the ones in the duels. Conversely, we can assume bit would have been worse, if it was Garcia seeing as he has the worst in the air percentage I've ever seen on a defender. Perhaps we might have controlled the ball better on the ground though.
These stats are not a full picture of stats talk less performance. But they hint at tendencies in those listed areas.
If nothing else those stats hint at the fact that John Stones might not be as bad as we think!