Welcome to the forum, your journey back to screens and tech is going to be tough, but we're all here to support each other even if it gets heated from time to time. Here's a run down of things to try/research.
#1 Try as many screens as you can and keep records, score each them, investigate the technology within each one. Hopefully you'll find some you can use, and from there you might be able to figure out why. Don't limit yourself, try old and new, try projectors, tvs, anything you can get your hands on. Sometimes the device the screen is plugged into is more important than the screen.
#2 xelaos As Xelaos says, try covering one eye with a patch and see if it helps - for some its a cure. Cover the eye, don't simply close it, for reasons unknown that's important. I made an eyepatch out of cardboard and string that covers one eye, but the eye remains open. Wasn't transformative for me, but in some scenarios it helps me a lot.
#3 Drugs and supplements, lots of things to try for migraines - there is a migraine reddit with a huge list of things to try. Some forum users get relief from cannabis.
#4 Diet: this one is primarily from my experience, but some foods make my screen problems far, far worse. Could be worth keeping a record of what you've eaten to see if you notice any patterns. For me, cooking oils are big trigger, but there are others including coffee, alcohol and spices. My overall symptoms have been in remission since I cut out red meat and diary, but its taken years for the improvements to show - I primarily did this to treat IBD and its working, but I'm quite sure the concurrent improvement in my screen tolerance is not co-incidence.
#5 Find something that helps you recover from your symptoms faster. I'm lucky now that a short walk is all I need to feel better, but I've also learnt that alcohol works in an emergency.
Lastly, this isn't going to be a quick process. You might get lucky early on and find a screen you can use, but I'd expect it to be a marathon, not a sprint.