VR still comes with a few downsides, with one of the most notable being motion sickness. Even if you are not the kind of person who gets motion sick on a boat or airplane, some VR games may make you feel dizzy or nauseous, ruining what should be a fun experience. Experts think motion sickness is primarily caused by a mismatch between cues sent to your brain. If your eyes see one thing and your inner ear is experiencing another, you might experience nausea. You may be more likely to experience this in certain virtual-reality games than others, depending on how the experience requires you to move. It is possible to mitigate some of these symptoms.
First, make sure your lenses are clean and that your IPD (interpupillary distance) is set properly on the headset, if it offers IPD adjustment. If you wear glasses, you can often find this value, in millimeters, on your prescription. If you do not, you may just have to adjust it while in-game to find the right setting. Also, try to accommodate your glasses in the headset by adjusting the strap or using a glasses spacer on a headset that offers them. Once you have the basics out of the way, you can start digging into your games' settings. Some games also offer a field of view (FOV) adjustment that can help as well. Finally, start slowly and do not force yourself if you start to feel sick.
More information:
https://www.wired.com/story/how-to-reduce-motion-sickness-virtual-reality/