It's not one thing causing the issue, it is several factors that all add up to create the issue. If you can remove one or more, you can sometimes drop below the threshold of what bothers your eyes.
This is why people find some solutions by mixing and matching and using different sources. They accidentally remove certain factors and the issue drops below the threshold for them. Everyone has different thresholds so one person may be able to remove one factor and be fine while another needs to remove several.
However, mixing and matching almost no longer works and within a year, it will not work at all. Too many new factors are being added in that no mix and match of components will be enough to drop below the threshold for most people. For example, people with old hardware who update to the latest Windows 10 say they suddenly have problems. So should they move to Apple? Oops can't do that, Apple OS updates cause problems to.
As for streaming, yes different streaming sources use different methods, even within the same company. For example, I can watch some shows on Hulu, but other shows give me an instant headache. Also, Netflix uses some kind of variable framerate technology. So if your internet is good one day, Netflix may not bother you. But if the next day your internet is slow, the framerate may drop to a level that causes you issues.
This is why I believe mixing and matching components is a waste of time, at least for the long term. It's almost pointless now and soon will be totally useless. It's like phones, most people agree there is almost no new phone that usable at this point.
The trend is that the number of devices that are usable are going DOWN, not up. That's the trend and only the trend matters when predicting the future. So I disagree with the poster who says that there are plenty of combinations that can be used if people just tried them. That facts simply don't line up with that assumption.
The only way to solve this problem is to work with the manufactures. Constantly buying and returning products is a fool's errand.
My big hope is that as they do use more and more tricks to increase resolution, that it starts to effect more and more people, eventually forcing manufacturers to address the issue. I think we are already seeing that, with Dell and others putting out "eye safe" products. They seem to know there is an issue.