Follow up:
Using the sRGB profile on my MBP 2021 M1 Pro reduced my screen strain by 98%, without needing BetterDisplay. BetterDisplay's virtual mirrored screens didn’t impact my strain at all but they did lower screen quality (color banding). The sRGB profile unfortunately disables brightness adjustments, but the default brightness is generally suitable.
karthi3219 I can't decide whether this setup is any better than the default macOS setup + sRGB profile. Watching movies on this setup can be problematic due to severe banding in dark scenes. Yet, during daily tasks, I don't notice the banding. After the BetterDisplay trial ends, I'll revert it to the default setup to see if I will miss it and it's worth purchasing.
Note: It's still unclear to me why only the color profiles starting with 'Apple' allow for brightness adjustments. Is it the same with you?
karthi3219 I did manage to set it up after your last instructions. I've been using that setup eversince. However, in bright environments I find it hard to use because the display is too dark.
What version of macOS do you have? When I go to System Preferences > Displays, I see
And whenever any of the non-Apple color profiles are chosen on the main display, the brightness is reduced to quite dark and it is not changeable:
When I attempt to change the resolution with BetterDisplay, it jumps back to 100% after I change it:
and this 100% is not particularly bright. I can use it but in a brightly lit room, it becomes hard to see and I must switch back to Apple P3 in order to get some more brightness.
karthi3219, it's heartening to see, in such a short span, that others are experiencing the same symptoms as I am. This indicates that my symptoms are not so rare, and there are many others in my exact situation. The response from Apple Accessibility quoted above gives me hope that this issue might receive the necessary attention and improvements will be forthcoming someday.
I hope that someone, who can help make a difference, will stumble upon this post someday and help set things in motion that lead to Apple fixing this issue for us. So, if you, the reader, know someone working with the display or GPU technology at Apple or know just someone working at Apple who might know someone, please do pass on this message to them!
I've already tried reaching out to various people at Apple and Nvidia who are experts in GPU architecture. I hoped they could make educated guesses on what might be causing these headaches and eyesores with newer Apple devices or what possibilities would there be to find a solution or workarounds. Unfortunately, I've yet to receive any response from any of them. I attempted contacting Barak Shahar, William Xu and Guanlan Xu (GPU design managers at Apple) and Tong Tong (Senior GPU Hardware Engineer at NVIDIA) via LinkedIn.
I'd like to try the method you described, but I apologize, I'm struggling to understand your explanation. Could you provide more detail, or possibly run your instructions through ChatGPT to generate clearer versions of them, so that I could understand exactly what steps I should take?
FWIW…
For a long time I was staying away from newer Macbooks because when I purchased my 2019 16" MBP, it instantly gave me grave eyesore. The first days I could not figure out why my eyes were hurting and I thought I was getting sick as this is when that usually happens to me. But spending the first weekend without the new Macbook and getting the eyesore back instantly when opening the lid on Monday morning got me googling and discovering ledstrain.org.
Eventually I figured out that SwitchResX+Millions of colors made the eyesore tolerable (not the same as my old computer but tolerable). Then I had a good chance to sell it so I did to gather some money to buy some M-series Macbook as I heard they are really quiet and fast.
But as I occasionally got the chance to test drive some M1 and M2 Macbook Airs, which were given me to perform the initial setup and installation of software and data migration from users' older Macs, I learned that they were just as aweful as my MBP was out of the box, but SwitchResX wouldn't allow to reduce colors to millions of colors on them either, so I aborted the plan to go for M1/M2 and so I was stuck on my old 2013 MBP I had lying around.
However, someone suggested me to try if the ProMotion displays on M1 Pro/Max were as bad on my eyes or not. Initially I dismissed this idea because I had already visited Apple shop to evaluate the displays of the new Macbooks and left the shop with sore eyes after 15 minutes.
But the other day I had some spare time and I went there again. I started from 16" M2 Pro. I spent about 5 minutes on it, scrolling web sites and playing around. To my astonishment, I did not feel the usual uncomfortable feeling in my eyes, so I left the 16" MBP and went to 15" MBA and I could immediately feel the uncomfortness in my eyes.
So I hunt down a nice offering for 16" MBP from eBay and ordered it. I have now spent about 3 weeks with it and I can tell that its display is way better for my eyes than the M1 MBA and M2 MBA I had briefly used before. But if the 2019 16" MBP and M1/M2 MBAs were giving me eyesores, this 16" M1 Pro is giving me a slight strain in my forehead, between my eyes but slightly above the eyelevel. And a liiitle bit of eyesore too. Like 1-2 of 10 if 10 is what my 2019 MBP was out of the box. I did not notice the strain in the forehead before with the MBAs but maybe it was because the eyes were hurting so much.
So the M1 Pro MBP is usable, although not 100% perfect. I'd say that the bump in speed and it's "coolness" and silentness weighs up the slight strain in my forehead it gives me.
Maybe this helps someone who has only tried MBAs.
Could it be that your devices have received software updates making them push pixels a bit differently to the screen which is easier on your eyes? Teams video may access the GPU directly and still use the old method.
Actually it's not the screens which are inferior, it's the way the hardware developers program the video card to output the image to the display. In order for the marketers to be able to claim that their particular phone or laptop shows billions (10 bit) of colors, the developers have programmed the video card to flip the colors of the individual pixels rapidly from one color to another, to simulate the color in between. Yes, the brain will be fooled and does not even see the flickering at all, but the eyes will strain from the flickering nevertheless.
Have you noticed how the rise of the dark theme craze conincided with the rise of eye straining devices? Long time I didn't undestand why people preferred dark theme so much, until I upgraded from my 2013 MBP to 2019 MBP in 2020. After 2 days of using it I felt that my eyes started to hurt every time I used it. I noticed that the pain started even after a minute of using it. That's how I found ledstrain.org. Eventually I found SwitchResX and switched from "Billions of colors" to "Millions of colors", and switched to sRGB, and used f.lux, and applied matte screen protector. After that it was a lot more usable but not so much as for example my HP Elitebook 820 G3 which gives me zero problems with eyes. Now I am back on my trusty 2013 MBP because the HP was too slow.
By the way, you can make the same screen which previously did not affect your eyes at all, make your eyeballs feel they are burning from behind by attaching the display to a video card which employs temporal dithering. And why it happens? It's to impress you with wider color range, because if two screens are side by side in the store and the rep says "this one is capable of showing more colors and costs the same", which one would you pick? I myself cannot distinguish between millions of colors and billions of colors, without looking the same image side by side but I can distinguish which one uses temporal dithering without any reference in just a few seconds.
Maybe.
Actually I don't have eye problems any longer.
What I have done:
I'm not sure which of those helped or I just adapted.
deepflame left the daemon of “SwitchResX” running. At first it seemed that having this tool enabled all the time also has a positive effect. Not sure if it is just placebo though…
Maybe it's because it put the screen to Millions of colors (https://photos.app.goo.gl/zXocAiFrJWRxCNfz7) instead of Billions which would activate dithering. Just a guess.
Actually I have a Macbook and I was going to try an old Windows 10 with Boot Camp but I encountered an error message during the install phase (Windows could not update the computer's boot configuration. Installation cannot proceed). Turns out that new Boot Camp and old Windows 10 are not compatible any more. Googling that error gave a fix to "use the latest windows 10 iso from microsoft". 
Which version is the last safe version:
https://photos.app.goo.gl/VePEedjcafrHdtHW9
?
Okay, I have now done some more extensive testing. I installed another macOS virtual machine using Parallels Desktop onto my Mac. Then I installed Parallels Tools on it to get other resolutions besides 1024x768 and then I set the same resolution (the default retina one which macOS ships with) on both computers (virtual and real), then I opened the same web page in full screen on both of them and aligned the pages to be pixel perfectly at the same scrolling position. Then I swiped with three fingers from left to right and back again to switch between the computers. I tested that way very long time and I concluded that:
) and applying a little bit pressure between your palms.This came to my mind while I was doing the experiment: https://youtu.be/5KiLVOAK7U0
All my Macs are running Catalina. Maybe it's the video card drivers: my old Macs have old video cards for which Apple maybe hasn't bothered to implement dithering while it has for newer hardware. When I look at Windows 10 login screen background image (you know, the one with looking at a beach from a cave) through Teamviewer, I see the that the color space is quite narrow, as the sky in the image has clearly defined areas of different shades of blue. That tells me that if there is any temporal dithering or other high frequency pixel flickering, Teamviewer filters that out.
Yes, I have big problems using the Mac outside of Teamviewer. I still own a 15" Macbook Pro Mid 2014 and 15" Macbook Pro Late 2013. I don't have any issues with those. Only with my new 2019 16" Macbook Pro. The issue is that my eyes start to feel burning sensation pretty much immediately when I look at the screen. I have moved the matte screen protector from my 2014 computer to 2019 one (the previous owner had it installed to protect the Mac's aftermarket value) and it helped a little bit. I started to use Iris Pro and it helps also a little bit. But I still feel the desert in my eyes within seconds of looking my Mac. But when I put my Windows virtual machine to full screen or when I put Teamviewer to full screen and look at my colleagues' screens, my eyes immediately relax. I actually feel muscles around my eyes immediately loosen up when I switch to Parallels or Teamviewer.