Alternatively, tablets with the Kindle app work quite nicely for textbooks.

I replaced physical textbooks with an iPad with the Kindle app on it, since whether it's an iPad or textbook it's something that stays at home. It works really well, especially side by side with Goodnotes for studying.

Kindle Print replicas can be okay but they are basically just PDFs. It's still faster to flick through a book than a PDF. If a non-print replica Kindle textbook has equations it's generally done with images and looks really bad, makes the book really big in size and slow to navigate, the equations can't reflow and so are usually noticeably different in size at every font level.