Hi Thuffam,
Board sizes have been getting larger for a few reasons.
1. You get more pop from a larger board
2. Kites have so much better upwind ability that you don't need to edge hard to get a board to go upwind.
3. Early planing is a big deal in a lot of countries so bigger is better.
The right board for big air is more determined on your local conditions rather than anything else. If you are in smooth water, you can ride a stiffer board allowing you to load up to the fullest. Boosting in choppy water is better to use a board with more flex to maintain control on loading. In surf, for sure a stiffer board with more rocker would be more ideal.
Having said that, The 2023 Duotone Jaime was designed with big air in mind. The stiff flex, mid rocker and aggressive tip channeling all aid in keeping a strong bite in the water. The reversed angle rail tips are designed to bite into the water and give max hold right until lift off.

A lot of the big air bandits in Perth are riding the Carved Imperator as their weapon of choice, expensive but extremely impressive board.
As always, go visit your fave store and grab a demo of the boards you think will be ideal and see for yourself.
DM