ISO Junk-free Epub viewer for Android

Hello and thank you for checking out my post, as well as any possible help you may provide.

I'm looking for an Epub viewer that is set up as just that, a viewer and not a 'reading' app.  To elaborate, I use my tablet to study, currently I use Adobe PDF reader.  I enjoy it because it's set up with a file browser, go into the doc and it's just there, no bloody bookshelf or pushed notifications, it's free and it's ad free.

I've tried a range of Epub readers and thought I might find help here in my search for one I can stand.  From "Seasons greetings" notifications to "Check out this book in Our store.  No?  We'll ask again in five minutes..", it doesn't take much to erk me towards an app.

I just need to be able to highlight and underline, of course be able to read it and looking for a simple file browser style interface.  I wish to move from PDF to Epub because of the ability to pop up from the page a full quote or reference that is embedded.

Thank you for your time and responses.