Well, getting your fakie Ollie down really well should help, and practice regular kickflips a little more. Pay attention to getting your feet to land in the proper spots, and always jump straight up, with your body weight centered.

try doing kick flip holding to a bar

Try leaning a little bit forward

Reste bien au dessus de ta planche

Jump higher and keep your feet as they are when u lift off

Lean forward a little more

Try to visualise doing the fakie kickflip stationary when rolling fakie, being centred over ur board and not having to much speed that will throw off ur balance, this helped me

Flick front of board harder