That's what the research says. It is not an opinion of mine. Eye strain may also be defined differently. https://www.mayoclinic.org/diseases-conditions/eyestrain/sym...
I have had success with OLED screens with black backgrounds and red font
It also specifically mentions glare and reflection being part of the problem, something eInk displays are better at than normal displays IMHO, because they don't project light at your eyes.
Do you have any links to "the science" here? Because a quick search seems to pull up a few things supporting less eyestrain from eInk than other screens, regardless of resolution. For example - https://pubmed.ncbi.nlm.nih.gov/24386252/
I hope that whatever you link to takes into account different screen technologies too - I can understand that it makes a difference on back-lit LCD monitors, but I'm going to take more convincing that the same necessarily applies to eInk tablets, as that would contradict personal experience as well as other material I've seen.