One other thought.

I know two people who tried hypnosis for other things. One guy used
it to get through nicotine withdrawal. The other guy stopped
stuttering.

The smoker, that was ok. He was motivated (new father) and he just
had to hold out for the withdrawal period. The stutterer figures it
was a mistake -- he was hardwired for stuttering and the hypnosis set
up a tension -- that finally broke when he experienced a big scare*.
He started stuttering again after that, but felt more normal.

If your motion sickness is a software problem, maybe hypnosis would
help.

Don
*He and his wife survived an airliner crash that killed other pax.