diop So, my issue started in 2010 when my partner changed the lights on our Christmas tree to LEDs. The new lights made me feel "unwell." Later, we purchased a new flat screen TV that made me "unwell" to walk by, and unable to watch. I didn't figure out that it was the LEDs that caused me to feel off, until I moved to a community that had LED street lights. It just so happened that LED headlights also became popular at the same time. Then cell phone screens started to trigger me. For me, my reaction is now instant and strong. Depending on the brightness/type of LED, my reactions accommodate to create a greater sensitivity. For example, my mom turned on her iphone X about 15 feet from me and I had an immediate and harsh reaction - it felt like she slapped me in the face with her phone.
I do have old tech that I rely on. Actually, I'm trying to replace my Moto G4 Play right now. I replaced my first, and have replaced the screen on this one three times. It's time to upgrade. I can successfully use my newer Acer Aspire E 15 laptop without a problem. And I purchased a Sony Bravia TV four years ago, as I learned that all Sony Bravas at the time were flicker-free. The only time I've had an issue watching the TV is watching a newer movie with LED headlights or emergency lights.
I agree; a bad device is a bad device. I can usually tell if a device is going to work for me in the first second my eyes see the screen, or within one minute.
Funny, I spent a month in Italy traveling up the west coast in 2018 and only got triggered three times. Each time it was from an item that could be purchased on Amazon. It seems that there are higher standards in place there then here in the US.
My primary care physician did his due diligence and sent me to a number of specialists. All tests came back clean, which is why I was diagnosed with FND.
I hope this helps.