I don't disagree that PAs is an indicator of ability, but it also depends on context. Arraez is the type of player that bats leadoff (and he did a lot), so that in itself typically creates extra plate appearances compared to a power hitter. And if this year's team had the number of injuries last year's did, Gallo would have more plate appearances than he does.
I was approaching it as, "If everything else stayed the same and you gave 2022 Arraez the plate appearances that 2023 Gallo has gotten, would the team end up with more runs?"