Given that Apple hasn't released a standard pixel matrix since the iPhone 3GS (480x320), be glad Sony wasn't afraid to go there as Apple chooses some really funky matrices. The one saving grace is that the + phones are at least a 16:9 aspect ratio (everything needing to be upconverted by 15%). A movie on the iPhone X seems likely to be a smaller image dimensionally than it is on the + models due to the unusual ratio (and of course the notch being wasted).
The Ultimate Guide To iPhone Resolutions
This is true except for the + model, at least it is standard on the 6+. 1080x1920. From what I understand the X can do 16x9 full frame of the movie but the screen is smaller to squeeze the vertical into the smaller form factor. This puts pillers left and right of the screen. I see your link also claims true 16x9 on all the plus models.
The other poor design in the X is the stereo speakers being both left and right at the bottom or right side ( in horizontal ) of the phone. Sony got it right as their tiny speakers are left and right of the screen. Of course for legitimate stereo on the X you should use the airpods and then the stereo will be proper.
Actually, I watch more You Tube content than movies. Most of what I watch is in 16x9 and lots in 4K now. Looks really great on the Sony vs. my iphone6+ The Sony only does 4K when the inbound is in 4K. If not then the screen defaults to 1080x1920 on the 4K pixel LCD. They did that to save battery as opposed to upscaling all the HD content to 4K. I'm not sure how they actually did that. The main use I do with the Sony is to view 360VR 3D in my VR goggles.Besides Don, how many people actually watch movies or TV on their phones?