I recommend checking out many of the videos in that channel.
For example this video talking about hinge neck posture. I would recommend that you check whether you have this posture. There should be no buffalo hump at the base of the neck: https://youtu.be/cUjoFwiGN-k
My takeaway is that several neck muscles (scalenes, SCM, longus capitis, suboccipitals) are way weaker than they should be in cases of eyestrain and headaches. Eyestrain itself could be related to photosensitivity caused by chronic mild intracranial hypertension, which can result from neck dsyfunction.
While it is true that some screens are better for us than others, I still contend that this set of issues may result from broad neck dysfunction (poor posture and weak muscles). How it manifests in the eyes may differ, but that doesn't change the underlying problem.
Since this can all be a bit overwhelming, I would recommend starting with only one thing. Do the following exercise for the scalene neck muscle: https://youtu.be/eVZBPJ39zVY. Check how easy it is to do. If you find it very difficult, that means the muscle is very weak and rehabilitation is needed.