Unlike the 2024 comparison Sinner vs Alcaraz, where the only advantage the Spaniard has on his side is that of h2h, 3-0 which, however overwhelming, had 3 matches that were all rather balanced, the Alcaraz vs Zverev comparison already makes more sense to be placed to subvert what the ranking says.
Alcaraz has won more tournaments (4 vs 2), has an advantage in the h2h (2-1) but above all he has a 2-0 in the slams, to which to add the Olympic silver (while Zverev went out in the qf vs Musetti) which does not give points but which with such a minimal difference in the ranking must all the more be taken into consideration in the evaluation.
In general yes, Alcaraz had significantly higher peaks than Zverev but the German was more consistent.
For me, as others have said, 2 slams won against 0 are enough to tip the balance of this 2024 decidedly in Alcaraz's favour.
And I would have said the same thing even if Alcaraz had won the US Open and despite this Sinner had remained number 1 in the world, at that point with an overall seasonal tally in the slams 3-1 in favor of Alcaraz, how could you prefer the season of Italian compared to that of Spanish?
Hypothesis which among other things could also have been verified last year with Alcaraz who after the US Open still had the possibility of finishing at number 1 despite Djokovic being ahead 3-1 in the slams.
So I choose Alcaraz's season even if Zverev were to win the ATP Finals, even if in this scenario he would get even closer, let alone now where the verdict in Turin is still yet to be written.