yeah stuff like this is really hard to truly quantify or find meaningful info. ONe thing I'd love to know is how much leeway the catchers have in calling a pitch that maybe doesnt fit with their cheat sheet. Like, in certain situations if they have a read on a hitter than he is sitting on a slider, but the cheat sheet says that the slider is what they would want to go to... can they change it up at will on their own?
Plus with guys like Bassitt, he's calling his own game because it would take far too long for a catcher to cycle through all 17 of his pitches and locations in the pitch clock timer, so basically any of his starts this year wont be usefull data in catcher game calling.
Relievers... most of them have two pitches, so calling pitch A vs B probably doesn't mean a whole lot if the pitcher doesnt execute. Plus... you'd need to separate the team with good hitters vs bad hitters and see if there's a difference with one cather vs the other vs similar strength lineups. Youd also have to consider platoon advantages, if one catcher seems to catch more PAs with that going his way... there's so much noise and nuance to this kind of thing, that it makes it exceptionally difficult to find meaningful numbers