I’m not sure I understand your concern. If the alternative is getting an Android tablet or iPad then I agree that being locked in a previous version of the OS can be a disappointing experience, but the Boox devices are primarily e-readers which, since they run on Android, can also double as tablets for some tasks. When you compare it to the other e-ink alternatives, I’d say the Boox devices probably age the best, since even if the company drops support you can still find APKs around to make new uses. As for the basics - reading, taking notes, browsing occasionally - you’re already well suited, so no need to worry much about upgrades.
Mine is the original Nova Air and (as you can probably tell) I like it a lot. What other choices are you considering?
Pretty much all of these devices feature touchscreens now. I use the original Boox Nova Air and I think it’s great.