What after Faber level 5

Hi there!

I will soon (in some months) be finishing with the faber level 5 books. And now I wonder how to continue in my case. At the moment I am doing scales/arps, a dozen a day, sightreading and Faber stuff.
My piano goals for the future are playing songs by ear (I will go over the Improvise for real book) and understanding the theory behind chords, and learn more complicated and fancy chords and their progression in a key and how to make it more "jazzy". I don't particulary want to play jazz, just to have knowledge about jazz chords and progressions and stuff to then use in my own music in the future, since I am planning to write more pop/film kinda stuff and not really do jazz. Classical repertoire is also fun for me but i don't want to limit myself only to it.
So i wonder if there are any "method" books or something that explains deeper theory and chords and jazzy stuff that you would need in modern pop enviroment, without hard on jazz stuff. Or would a jazz book (Siskind) be okay for me in this case anyway, even though my end goal isn't jazz? I don't know how to continue.

I don't want a teacher.

Hopefully I didn't ramble too much, thanks!