This has been sort of solved since 2016, when Ubisoft released Eagle Flight for PCVR/PSVR, a 1st person "eagle in Paris" simulator using head movement as its primary control. Its locomotion approach made it a prime candidate for triggering motion sickness. Ubisoft as an AAA studio wanted to ensure comfort, so they did a lot of research and ended up with two main solutions.
First they always showed the eagle's beak as a visual fixture, providing an "explanation" for the mismatch between what the eyes and the vestibular system in the ears report, which is the main cause for motion sickness. This also works in car simulations by keeping the cockpit fixed to the users head rotation, even if it doesn't make physical sense.
And secondly by dynamically limiting the FoV. A higher FoV causes more motion sickness especially during head turns, so they introduced a dynamic vignette reducing the FoV only during head turns. They somewhat overdid it, and AFAIR there was no way to turn it down, but this actually helped with reducing motion sickness.
We have known what triggers motion sickness, what can be done to prevent it at least for most people, and what developers should avoid doing for a decade. Most games now come with a number of comfort feature, though often these should be more fine-tunable by the users, and should be properly explained to those that in their search for maximum immersion switch of everything, not necessarily understanding why these things are even there. And of course a lot of developers never bothered to learn how to properly design for and implement comfort in VR games.
