I would suggest Kobo. You can easily install Koreader on it. Then when you want to transfer books, start an FTP using your phone's file manager, and connect to it from your Kobo's koreader. This is how I transfer files wirelessly from my phone to my Kobo. If you're worried about the effort or skill it would take to install koreader, don't be. It's as easy as connecting to your computer and running a script.
This is amazing. I saw YouTube only showing a search bar when I went there, and it was liberating. I could search and watch the video on the topic I wanted, then promptly leave. Without all the Hot and recommend shit being shoved down my throat.