I've been using a Onyx Boox Note 3 for a couple years now (I previously had a Remarkable 1 but it didn't stick for me) - it has Android 10 (w/ Google Play support) and even an SDK for responsive writing for 3rd party apps. It's been great for taking notes, and adequate for reading books and papers (although even a single color for highlighting would be a huge improvement).

Note, that Onyx is notorious for violating the GPL (it doesn't release kernel sources), while reMarkable is not only compliant, but much more hacker friendly in general: https://github.com/reHackable/awesome-reMarkable

But there are also other companies/products Boyue Likebook, Ratta Supernote, Quirklogic Papyr, Fujitsu Quaderno that compete in the e-ink notepad space as well. I'm keeping an eye on the Bigme Carve Color personally, which basically has all the hardware specs you'd want and color (Kaleido 2) to boot: https://www.youtube.com/watch?v=Ydo5FtSt_qQ

For those looking at color, it might be worth waiting a few months to see if 1) if the Reinkstone R1 is actually vaporware or not (it has an alternative DES that looks like it provides better looking color, but is being developed by a questionable Chinese company that's been best by delays) and if eInk's Kaleido 3 is a significant improvement.

For those interested in the relatively niche world of e-ink devices, I highly recommend MyDeepGuide as a good place to start: https://www.youtube.com/c/MyDeepGuide/videos