messi for the nt is mostly a central player, the typical false 9 that he played with guardiola. lautaro is a 9, so messi has to play a bit more wide to confort him when martinez is on the pitch.
dybala would be a better fit with a central messi as dybala is the best when he can play a sort of inverted player from the right (not a winger, different skills and tasks, but the positioning is similar)
i also think it's purely personal to not play dybala. i have no idea why they even called him up