-strong passer
-strong tackler
-secure stopper
-composed and positions very well
-youth and potential to mold perfectly to our backline
Compare his stats in his own team -
Strong tackler? 11th best in the Real Sociedad team
Secure Stopper? No idea what that is based on
Composed and positon? 5th best in team for interceptions and 3d best defender.
Passer? 13th best pass rate in the Sociedad team last season.
So when we say that his actual gameplay shows he's strong in the air despite not being tall, you point towards stats.
When stats justify that he's been "better" than one of the best headers in the world, you throw that evidence out too and say nothing suggests that he's good in the air.
I have watched plenty of games of his and never considere him a dominant player in the air.
The fact is that he was nowhere near one of the most dominant players in the air this season in La Liga. Not even close.