As far as I’ve seen/read they don’t really do sales ever, but sell open box good condition items at a decent discount.

I have the smaller one, and text looks a lot better than my Paperwhite from 2015, but I haven’t spent a lot of time with a newer Kindle for comparison or looked at manga on either. Even with a magnifying glass you can’t see individual pixels on the SNs though so I would think graphical content would look good?

I recently got a supernote, same idea but a bit cheaper, they offer a smaller one, and it runs an android fork instead of a Linux fork. Great for notetaking, haven’t used obsidian but you can side load almost any android app with mixed success