Wow they surely hate protonmail

Correct, they announced it two months ago: https://www.androidpolice.com/bitwarden-app-about-prettier/

Same, staying with bitwarden for now

I checked a few samples, for all there was at least 1 chapter as a preview. But it differs, one also had 3 with around 40 pages. I only counted actual pages, not into, table of contents etc. Hopefully that gives you an idea!

I usually buy them on my phone (Kobo app), which is easier with payments. Afterwards the book is immediately available on my e-reader. Started doing this a couple of months back and I like it. You can also preview books, but got no personal experience with that.

This would be amazing