I have an Onyx Boox Max Lumi. It's a few years old, and obviously newer models are improved, but I'm pleased with the product. My intention was to splitscreen with PDF textbooks on one side and taking notes on the other. It works great for that. It's probably larger than most people would want, but it's perfect for this use case. I can also use it to read digital magazines at a decent size. Smaller tablets would not be as comfortable to read on.

MyDeepGuide is a Youtube channel that reviews different products, the bulk of which are e-ink tablets and accessories. https://www.youtube.com/c/MyDeepGuide/videos I'd certainly recommend going through the channel before anyone decides on their first tablet. I did, and the Max Lumi was exactly what I expected due to detailed reviews.