Samsung has no desire to spend more money on the display for higher frame rate, for a while now Apple has used better screens on iPhones than Samsung. LG is selling the
OLED65C8PUA tv which is 120 Hz OLED, but with a price tag to match.
I think there is a 40% chance all these will be characteristic of the 2019 iPhone XS Max successor. If they want to give it higher battery life than the XR they probably need it around 4000 ma/hr, the higher wattage charger to match makes sense. Of course it will be thicker because of those. The 3 cameras has been a rumor for a while and would make the XS max successor more distinguished from the XR successor. Lastly the 120 Htz display makes sense as Apple tries to usually give the best display to iPhones while the iPad already has it. The rarity of OLED 120 Hz is still pretty high, but it is very likely Apple will have the first one on a smartphone weather if it's this year, but they most likely won't next year because of the S generation delaying it to 2021.
TV OLED and Phone OLED are not the same, even though the name is the same.