Alcaraz didn't play at the ATP Finals in Turin last year, but he was in Italy to receive the year-end trophy as he finished the year ahead of everybody. He's got a pretty decent chance to do so again, even though it will take some undertaking, and he'll need a bit of help from Novak Djokovic.
The Serbian is number one right now but is defending a lot of points until the end of the year, which isn't the case for Alcaraz. If he continues to play well and wins a few events, then he'll likely end as number one. Daniil Medvedev certainly thinks it will happen, as he shared at the 2023 China Open.
Everywhere I go I seek to become champion, so the dream of being number one remains alive. But I know I am very far away and that my fight must be more about trying to finish in the top 2 and staying close to the top to be able to attack it at the beginning of 2024. I don't think Novak will play too many tournaments, so logic indicates that Carlos would have to finish as number one at the end of the year.
Medvedev, of course, was number one, but he didn't remain the 'best player in the world' for too long. He'd like another crack at it and could certainly do it, but he'll need a spectacular finish to the year, which isn't impossible.
It is unlikely, as he explained, that Carlos Alcaraz has the best chance to do so. Whether that happens will mostly come down to himself but also other players. Perhaps Medvedev wins a few events and becomes year-end number one. Time will tell.