I'm from another country and don't know English well, but we also have popular forums where phone flickering is discussed. One user bought a microscope and started checking screens for flickering.
So far he has tested the iPhone 11, Huawei Mate 20, Incell from manufacturer RJ for the iPhone 12 Pro Max, and screens from manufacturers RJ, JK, EK Pro, TC for the iPhone 14 Plus.
The iPhone 11 has a noticeable strong Temporal Dithering that makes many people's eyes hurt, the Huawei Mate 20 and iPhone 12 Pro Max with the RJ screen had a flicker that was hardly noticeable and these screens are suitable for the most sensitive people. The screens from the JK and EK Pro phablets noticeably flicker, straining the eyes a bit, these screens may not be suitable for everyone. Apparently, in new batches after the iPhone 12, the RJ factory changed the technology of production of displays and now the flicker appeared on the edges of fonts and on some colors, eyes can be strained. The screen from TC factory turned out to be the worst, straining my eyes a lot, in addition to that it is also extremely low quality.
I attach a video of its tests, where you can clearly see the presence of flickering. If anyone has the opportunity to test their phones in the same way, especially among those who use incell screens, it would help everyone a lot.
It doesn't require any special skills or equipment, just any microscope.
Video