I have enjoyed the Android app "Librera PRO" from f-droid.org for reading ebooks/pdfs, once I got familiar with it. Much easier than reading in a web browser.

• One can download an .epub file from somewhere like gutenberg.org.
• Having explored its features and setting all the options to my preference, I like it.
• For example, one can turn pages with one tap, instead of a scroll action.
• Then while reading, I might listen to the RadioDroid station "Your Classical - Relax" or some slow swing... :)
• It comes from the free app store whose .apk file one can download at f-droid.org , then "side-load" (install).
• Something else to relax sometimes, is skim "English literature" (or such) in wikipedia, then go read books by them on gutenberg.org (or archive.org? etc).