Checking in again, this same Lenovo IdeaPad Yoga 13 1st Gen + Windows 8.1 + screen sharing setup is still awesome for me.
The "server" device has also been migrated to an M1 Air instead of an Intel MBP to run some more demanding macOS apps and things are still going smoothly.
There's really only one main catch to be aware of for the screen - (lining up exactly with what many others here have said about many Lenovo laptops!), the screen is the most comfortable when running on battery and not plugged in. That's when it achieves pretty much zero strain.
However, if it's plugged in, I notice some slight strain and unusual flicker. This isn't a new issue, I'm just deciding to point it out now. Likely theory is that there is interference from AC power that somehow reaches the LCD. Even in this case though it's still many times better than any (even older) Mac laptop, but the way you achieve maximum "stillness" is to run it on battery.
Sometimes (at least to my eyes) it seems that after returning to battery you need to toggle ditherig.exe to Spatial and then back to Disable in order to fully get back the stillness.
As I've previously mentioned, mild (i.e. "low flicker depth") PWM on dark grays is still detectable on the Lenovo at all brightness levels in both power states. However, even though I can't stand most PWM or flickering lightbulbs for instance, whatever type of mild PWM is used here somehow remains totally fine for me. No issues as long as I'm on battery.
100% brightness also remains the best (even though PWM can still be detected), this might just be since the screen has low nits so running it at max is pretty much necessary anyway.
Again, simply using this laptop literally makes me feel a hundred times smarter than I thought I was. It's incredible. It really makes me think how many people's cognitive / learning ability could be entirely transformed if they just had a healthier screen in front of them.