I recommend trying the Boox Palma, I have similar issues to you i.e. can really easily notice the problem with all 1609 and later "composition layer" windows versions, and Intel issues for me can be traced back all the way to 2012 driver version 9 with HD 4000.
The Palma is a really nice break from all the modern screen madness.
I know that based on your post you're more interested by larger screen tablets, but if you've never gotten into E-ink before I'd still go with the Palma first to get an idea of what E-ink is capable of and the limitations in a form factor that's easy to carry around and experiment with using in a bunch of different postures and locations for the whole day instead of "tying" the experience to a more dedicated tablet. Then, if Palma works for you, start looking into the larger devices.
Originally I bought Tab Ultra first, but I wish I started with a pocket device instead since at the time I had no other screens that worked for me and was annoying to be tied to that tablet whenever I wanted to read something with the advantages of E-ink. With Palma I'm able to have access to that ability at all times, and then use my larger tablet for more dedicated tasks like taking handwritten notes.
(FYI, in the case of larger tablets, I do not reccommend Tab Ultra, the camera bump is unnecessary and essentially makes a case required, the screen texture is too glass-like for the stylus, the magnetic keyboard wasn't worth it and frequently disconnects or magnetically interferes with pen input, and mine has tons of issues with touchscreen responsiveness. I've heard that other Boox tablet series are much better than the Tab.)
E-ink displays aren't perfect:
the moving dither pattern while scrolling and sometimes while typing can occasionally get distracting. Remember that all fast refresh e-ink devices cannot display grayscale in the fast mode and thus use dithering to display all shades of gray. The issues here though are nothing like traditional dithering issues though, it doesn't really cause strain and only moves while interacting (as long as you turn Display Enhancement off for every app…) but note that the screen will look more jagged and grainy than expected, it feels like a screen made out of moving grains of sand instead of ink (unless you're in HD mode where its sharp and smooth like ink)
the forced full refresh whenever powering on makes it feel more difficult than necessary to pick it up and do something quick, not "instant-on" (which is technically a software limitation, as it's triggered by the OS and would be technically possible to turn on with needing this refresh)
and there's something about the cheap matte coating that Boox devices use that I feel makes the screen look hazier than it should be given the PPI. (Compared to e.g. Kindle Oasis which looks incredibly sharp.)
But any possible strain never goes above mild, and never is affected by what content is onscreen. The simplest screen with large icons, and the most complex dense diagram feel the exact same to my eyes which is a breath of fresh air compared to modern screens that "seem to make certain photos and patterns more uncomfortable than others". On E-ink, even a dense striped pattern doesn't trigger any "pattern glare" effects for me, which is really fascinating because I can experience pattern glare in the real world, but E-ink seems to be able to avoid it. Also, whenever you use it in direct sunlight outside, that's when it looks the absolute sharpest and most comfortable, E-ink is at it's best when outdoors. I'm typing this post from Palma right now 🙂
What I love about e-ink is that there's absolutely no "false 3D effect" at all (except for the physical fact that the white background is slightly behind all the black ink particle similar to old dot matrix LCDs), compared to even the most comfortable traditional screens I've found where there's always something that slightly feels like that. Photos are completely flat on E-ink devices, more than any other screen I've used.
Another reason why I recommend Palma for trying E-ink is the touchscreen responsiveness.
I have a larger Boox tablet (Tab Ultra) and I'm not sure if it's a specific hardware defect to mine, but typing is impossible on my Tab Ultra, it doubles and misses letters constantly if I type only slightly too fast.
On the Palma, the touchscreen works perfectly and I can type as easily as on a normal phone. Note that the best experience is with the SwiftKey keyboard, I make constant typos on the stock Android keyboard (which is true for me on normal phones too) but I can type extremely fast on SwiftKey and make no typos. It responds more like the iOS keyboard which IMO is better (for those like me who prefer quick two-thumbs typing instead of swipe typing). Note that there is no vibration motor and only sound feedback can be used. Hisense devices have vibration if that's important for phone typing for you.
Boox frontlights are not perfect either. Can't see flicker on camera at all, but they just feel kinda cheap and not like they were specifically designed for the device, and the warm light still has an obvious blue component. However, Palma front light is noticeably better than my Tab Ultra, feels smoother and more relaxing and the warm mode is much more warm. Still not perfect though. Again, best experience is outdoors in sunlight.