> As I understand it, Google requires Android devices to have colour screens and, so I've read, won't certify eInk eReaders for newer versions of Android.
The linked article says "[Device implementations] SHOULD support displays capable of 24-bit color graphics.", contrasted with "MUST" in other bullet points. So I'd say Android shouldn't be a blocker. That doesn't necessarily mean Google will happily license Google services including Play Store (possibly for a fee), but there are manufacturers that build their own app store, or just let users sideload apps. Worst case, just put AOSP on the device. The experience isn't going to be perfect, but it's usable.
I do find the really old android versions to be quite frustrating. I don't particularly know what I'm missing, but it feels so not good buying a device and seeing that under the hood it's Android 11 (2020).
I suspect it's mostly that e-readers tend to use pretty old chipsets, & that no one has bothered updating support in a long long time. Maybe perhaps possibly there is some technical gotcha but I expect its more an issue of neglect.
Whatever the case, incredibly discouraging. I've looked at Boox Palma's and others but heck no I'm not buying such a clearly unsupported unloved system.