One likely cause that's not mentioned so far, is that paradoxically the stomach doesn't produce enough acid. The sphincter usually closes when the stomach begins digestion, but this only happens if a certain pH threshold is reached. There are some receptors in the stomach that detect this pH level and signal the sphincter to close. The lower acidity output is typically caused by unhealthy diet and frequent meals. To fix it, apart from reducing the frequency of meals, you can ingest more acid, in the form of vinegar or lemon juice. This is counterintuitive but I can confirm it works, it helped me a lot to mitigate the problem.

Stress response depends vastly on the game. A lot of games will actually increase stress levels. Take Elden Ring for example, that game will make you sweat at almost every encounter. But it’s possible that this kind of exposure might make you more resilient to stress in the long tun.

I think one of the greatest barriers to VR adoption is not resolution etc. but motion sickness. It is caused by the conflicting signals the brain receives from the body and from the eyes. Currently the only way to get rid of it is through training, but I'm not sure how many people are willing to go through the process. It took me about a month to fully get rid of it, but I assume it vastly differs from person to person.