KM Thanks for the response. Now I understand what to expect from DC dimming. Sounds like it's more about luck as to whether you receive a flawlessly manufactured panel. Seems this is great solution for people who already own these phones, but for someone like myself who is interested in buying, it might be best to stick with IPS devices.
Just recently I was looking at the Sony Xperia XZ2 (as mentioned previously) but with PWM of 2,300Hz it might still cause problems. I only found out about my intolerance to PWM after owning a ZTE Axon 7 which uses 240Hz AMOLED (Exact same Samsung panel as found in the Galaxy S7 Edge). I was also looking at the Xiaomi Mi MIX 2S (also 2,300Hz IPS) but a lot of users complain about slow display response times which causes blurring of text whilst scrolling.
I have to imagine 2,300Hz IPS would be a lot better than 240Hz AMOLED, but I am very hesitant to take a risk with either of these phones because I don't want a reoccurrence of my headaches and eyestrain.