I was looking for a tablet for reading a few monts ago but tablet screens hurt my eyes so I bought a kindle paperwhite I used a burner account to get it working then put it in airplane mode. I sideload every book I read using calibre. Kindle was a pretty significant upgrade over a tablet I would recommend any e-ink display over any other display for reading.

And btw linux on a touchscreen is not a good idea yet. There are plenty of good book reading software on android so maybe you would want to install a custom android iso.