While I agree that there is definitely a chance that lack of true binocular vision/convergence insufficiency could be the culprit, we know from evidence that displays ARE employing flicker, and desktops also using dithering. Would you knowingly (even without discomfort) sit in front of a strobe light for hours on end?
I'm just suggesting that while relaxing the eyes could help to 'tolerate' the screens for longer, there may be neurological/physiological effects of using these displays that go undetected.
I am also in a small minority with Strabismus, and due to how I was born, will never attain binocular vision. So this method of vision therapy will not help myself.
I am aware that people with small deviations can practically cure themselves with vision therapy, so wishing you good luck. A book I highly recommend is Fixing My Gaze by Susan R. Barry.