So you should play shorter sessions and in between each session, you should take a 3-5 min. break at the City of Art and Sciences VR showroom.
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If you face the direction your car is facing, there is a building off in the distance with a sign on top of it displaying a company name which I can't recall at the moment. But if you focus your gaze on that sign for at least 2-3 minutes, it will both relax your vision and settle down any motion-sick nausea so you can go back in. I used a similar technique when I was playing Horizon Call of the Mountain and trained myself to do longer sessions without nausea.
I know you can also just wait for an update, but after seeing these videos I was already preparing myself for the motion sickness boost and this specific solution I discovered for GT7 VR.