when i go for the double jump its usualy off a KBA that the person didnt roll from so i relaunched them and they are a little bit higher so its easier to do i think.
When doing it off a regular launch try
launch, lp, lk, lp, slight pause double jump, lk lk cannon drill KBA.
launch lp lp even slighter pause lp lp slight pause double jump lk lk cannon drill BKA.
once u get that then go for the magic series after the double jump, tell me what happens
i use this combo cuz i think its easier to do a air reset, to do that, do lp lk lp and pause a lil bit longer but not so long that the opponent falls too low. (timing is crucial) when u do the double jump, double jump to the other side and hopefully they will block the wrong way if they remember to block and then ug et a reset for more damage.