Some update. I made another approach with HTC 10 and W10 on Macbook Pro, now with more stable setup and a prepared HTML page which makes a series of R, G, B decreases. Basically it starts with 255, goes down one step every 2 seconds to 245, then moves down to 225 (just to save time and don’t have to wait the whole spectrum), goes down to 215, and so on, until it gets to 0. It means that I go through sets of shades of Red, Green, Blue, everytime activating just one pixel.
To me it looks like these subpixels flicker. It might be subtle (however I saw ranges where it became more obvious), but it’s there. What’s more - I saw some kind of subpixel dithering where with pixels 1 2 3 4 , 2 and 4 were getting darker before 1 and 3, later it seemed to leave just one line of 4 brighter.
In coming days I plan to test it with IPhone where flicker should be more visible due to higher fps. Anyway, it looks promising. I think of testing dithering as well, not sure how to approach it though - some kind of soft gradient should show it?