What do you mean when you say PWM bars? With OLED displays each pixel is individually lit, there isn't any backlight that could show up in bars like it happens on some/older LCD screens. How noticeable PWM is depends mostly on the frequency it uses, last year's 13 Pro actually had a higher frequency and was better in that regard than the Pro Max. Unless Apple changed anything, the Pro Max is not great for people who tend to notice the flickering.
But some people can notice the flickering even at 500Hz and above, and would be affected by virtually all OLED iPhone screens.
But some people can notice the flickering even at 500Hz and above, and would be affected by virtually all OLED iPhone screens.