In my reading app (The Storygraph), you can track pages read, not just books read, so you aren't incentivized to choose just shorter books. I also am trying to read more nonfiction. I already read a lot of fiction, so I have set aside time 4 days a week to read something non fiction. For me, that's an hour on Sunday and thirty minutes on two weeknights. I always read a fiction book while I am reading a non-fiction book. I will finish several fiction books before I finish one non-fiction. My distribution is about 90% fiction, 10% non-fiction, but that works for me.