I think while it is a big decision for game one, who plays stand off for the majority of the year will answer itself through injuries, whose available out of the three of them and not injured, and who has been playing the best when they had their chances.
There was no pecking order between Metcalf and TMM in 2023 as one of them was always injured. So we don't know how Game one will pan out. The one thing we can count on is that CHT will definitely play NSW cup for the first 5 games next season to re-aclimitise him to rugby league.
I personally think they will wait all the way to the pre-season games and watch out of Metcalf and TMM who puts their hand up in those games. That sort of two game shoot out is more likely to favour Metcalf as people remember tries more than defence or try involvements where you weren't credited with the final try assist.