You may face problem with small size of text on screen.

If you look to book sizes they are usually 10" or 11" and has dimension ratio 1.2-1.5, with most common is 1.42 (which is √2 - A series paper size ratio).

It's better to have near the same ratio for a tablet screen to effectively reuse all available space.

I had N101 II tablet with 10.1" screen size and 1280 x 800px resolution. Screen ratio is:

1280/800 = 8/5 = 1.6

In portrait mode top and bottom space of screen are wasted as screen is too narrow.

Full HD resolution has worse ratio:

1920/1080 = 16/9 = 1.78

but there are usually additional pixels for menu (like in Samsung Galaxy Tab A 10.1):

1920/1200 = 16/10 = 1.6

There is Samsung Galaxy Tab S2 9.7 that has ratio:

2048/1536 = 4/3 = 1.33

It is much closer to book ratio and provides more space for text in portrait mode which is usual for books.

Another parameter is DPI - how precisely screen can represent details. Usual print material has at least 300 DPI for inkjet printers and 600 DPI for laser printers.

CRT PC/Windows monitors has standard of 96 PPI and Apple monitors has 72 PPI. But those numbers slightly increased with LCD monitors have come to play.

My old tablet has such DPI:

10.1" / √(1280² + 800²) = 150 DPI

Samsung Galaxy Tab A 10.1 has:

10.1" / √(1920² + 1200²) = 224 DPI

Samsung Galaxy Tab S2 9.7 has:

9.7" / √(2048² + 1536²) = 264 DPI

So I decided to buy Galaxy Tab S2 9.7 for reading because of DPI and more appropriate size ratio. Even though it has a bit smaller screen that 10.1" it is wider in portrait mode.

https://www.gsmarena.com/samsung_galaxy_tab_a_10_1_(2016)-8090.php

Samsung Galaxy Tab A 10.1 spec.

https://www.gsmarena.com/samsung_galaxy_tab_s2_9_7-7438.php

Samsung Galaxy Tab S2 9.7 spec.