Ask HN: How are you reading (nonfiction) books/pdfs in 2025?

Everytime I start reading a book, I feel like uploading it in NotebookLM/ChatGPT to get QA; but these don't let me read in their app, and its not easy to get digital copies of books. I also want to ask questions adjacent to what I'm reading easily; I wonder if there are great apps/hacks people have for this.