Do I need a tablet that runs Android, or a closed note-taking device?

It depends on how much you want to do beyond writing. Open Android devices like the BOOX Go Color 7 and TCL NXTPAPER tablets let you install reading apps, browsers, and email, while closed ecosystems like reMarkable keep you focused on writing and reading with fewer distractions. The trade-off is flexibility versus simplicity; buyers who wanted a single-purpose notebook tended to rate the closed devices higher in the reviews we saw.