I know a few people have posted on here asking about medical interventions that others have used, so I thought I'd share my recent experience, in case it helps anyone.
Background is that I am sensitive to many screens - older TVs are OK but pretty much any other LCD/LED/OLED screen will give me eyestrain, followed by a headache, followed by nausea, turning into a persistent migraine. I seem to have got more sensitive over time, with older monitors and devices triggering me that never did before. This led to me trying my doctor again to see if they had any ideas.
Their response was to view me as any other migraine sufferer, for whom the first action is to avoid triggers. As my triggers are nearly impossible to avoid in modern life, he suggested trying a prophylactic drug. Now I had tried this before (beta blockers) with no success but was willing to try, so he prescribed Amitriptyline.
Results have been surprisingly positive after a few weeks - I still get eyestrain and headaches from triggering screens but they now don't develop into the full migraine or nausea. This means that I still need to minimise my exposure to the worst screens and I probably get through more paracetamol than I should but I can at least get through a day's work with my least-triggering setup (currently a Win 11 PC driving a 2009 LG TV!).
Of course, it would be better to understand/fix the cause but that doesn't seem likely any time soon - so this counts as progress for me, and it means I can continue working.
A disclaimer is needed here - I have been prescribed this by a doctor, it may or may not be suitable for you. It has side effects but these are manageable (it makes me sleepy so I take it just before bed) - again this may be different for you. But I wanted to share this in case anyone here has got as desperate as I have lately.