StaticLCD Impressive seeing this be a top issue on the AOSP issue tracker
However not to rain on anyone's parade and while I don't know the exact intricacies of the "graphics pipeline" of modern phones I suspect there can be at least two potential issues leading to eyestrain "caused by software" (e.g not PWM). One being the GPU output of the device leading to temporal dithering or other "dirty output", which AOSP has minimal (if any) control over. The other being alleged changes in Android causing other rendering issues (and I might remember reports from others encountering issues updating the OS version on certain devices going as far back to Android 5/6, which is from circa 10 years ago). Doesn't make any of this easier, but nobody said this was going to be easy.
From seeing how the AOSP issue tracker has worked in the past a developer (or experienced enough user) submits a report (preferably with actionable technical details), someone at Google acknowledges it and eventually something happens at some point after internal discussion and possible development inside Google which will have a public update eventually. Don't expect much in the interim between the acknowledgement, except for possible clarifying questions. Such is the means of "siloed" tech companies unfortunately.