Across the board really. Although there is a major cautionary red light in that he spent quite a lot of time in the midfield last season, which naturally affects many of the stats you'd judge a CB on. So there's that, but it's more that I don't really see something very special when I watch him play, and when I turn to stats I don't find anything that contradicts that impression. I
am more or less assuming that I am missing something, because that
is really a lot more likely than him being bought for 50m by a major club and chosen for England out of sheer incompetence or blind faith.
Some of his better stats fit the expectation of helping with playing out from the back. And of course, he hardly has Luiz's capacity for brain farts at the worst possible moments. But the thing is, brain farts aside, Luiz was a player of major qualities, and White just doesn't look like he is, at least not yet.
As for the stats, for what they're worth given the above-mentioned caution, he doesn't really stack up impressively in any relevant category. His worst areas are Dribbled past, clearances, disposessed, aerial duels won and aerial winning %, where he's in the bottom 20% of CBs statistically. Obviously, some of those are affected negatively if you spend time in the midfield. Then there's a load where he's sub-average (lower than the 50 percentile among CBs): Passes completed and % of passes completed, interceptions, touches on the ball, progressive carrying distance, miscontrols, fouls committed, regaining the ball. There's few areas where he's okay statistically (50-80 percentile), but at least some of them are ones where you'll get better numbers if you play in the midfield: Passes into the attacking third, progressive passes, shot-creating actions, number of tackles and blocks.
I agree Ramsdale would hardly displace Leno while he is around, but will he be? And given needs elsewhere, I don't understand why Arsenal would spend that amount of money on a keeper unless they saw him as someone who will step into those shoes in the relatively near future (or why Ramsdale would make the move unless he's given assurances of that kind). He may be good enough to be a starter in the PL, but for a club who aspires to be top 4? I don't see it.