Same experience on a PaperWhite 2, been using it for a long time.
It is a good reason to look into rooting, PDF reflow and the function to remove margins make it possible (at least tolerable) to read PDFs when an .epub / .mobi is not available.
You can also run Alpine Linux on a rooted Kindle with graphical interface, I found it amazing but ultimately not that useful with the limited system memory.
Re:KOReader: Open-Source eBook Reader
by lotharcable2 on Tuesday April 01, 2025 @07:34PM
(#43552394)
PDF reflow is one of the major reasons I am using Koreader. The whole thing is very clever and works extremely fast given the limited nature of these devices.
There was some discussion about it on HN not long ago:
All Kindles can now be jailbroken | 1377 points by lumerina | 2025/02/17 | https://news.ycombinator.com/item?id=43073969
I found KOReader's Android app a tad buggy, but the experience is wonderful on Kindles. If you've got an old Kindle kicking around, I also wrote up a little thing about bringing them up to speed which mentions KOReader: https://vale.rocks/posts/improving-early-kindles