Environment is basically any. I used to read on my touchscreen 2-in-1 ThinkPad using Arianna from KDE.

But I stopped because of software annoyances.
At some point, native Arianna package broke on Arch. It’s fixed now, but the UI has changed. In the past, while in portrait mode it also shown 2 columns, just slimmer ones (I think that’s version 24, I am not currently on that laptop). Now it only shows 1 page in the middle of the screen.
I also have an old Flatpak version installed which still has the older UI (I believe the older native package didn’t work with current dependencies), but simply the knowledge of that thing taking up in total 4GiB (as it’s the only Flatpak I have) while the native version is 1.6MiB bothers me enough not to use it.