Both Peter and I have the A70 on Android 9 and the implementation of PWM on it is not an issue for us with the version of the hardware and software we have. The difference between it and other devices is probably a software driver because if I look at different versions of the Intel HD graphics driver on my PC across Windows versions and Linux, the experience changes and some versions are better than others. I also have multiple DP to various output dongles, and some are better than others as well. Incidentally, the HDMI port on the Intel NUC is an internal DP to HDMI adapter. Reasonable to conclude that it is the same with smartphones as well since they are small computers and we just got lucky.
I haven't updated mine beyond December 2019 patch on 9 because I am afraid of it changing for the worse so I have decided to just leave it as it is. I'm going to skip 10 entirely. I will consider 11.