If by “hard” books you mean physical books, then counterpoint: why do you want to go back to reading physical books if:

1. Your physical posture is better for your health without them
2. if molding/adjusting your environment to be book friendly is too costly (mentally/physically/financially/what have you)

Scratch all that, I noticed upon reading further down in your post that you actually meant cognitively hard books to digest. 😅

Otherwise:

• my favorite, or rather required, environment is outdoors. Indoors, I fall asleep from reading. I’d have to, figuratively, inject myself with caffeine or something to be able to read indoors. Here is one of my favorite spots:

bVZeKqsm2GcEwMP.jpg

• I digest each reading session by walking to and from work. I’m also single and have no (other) life, so I have lots of time for reflection. I also share my thoughts on the books with my family over Signal.
• I’m always prepared to take notes, carrying around a notebook and a fountain pen, but it rarely happens. Perhaps if I had somebody in my everyday life with whom to share my notes? Even then, I would have to feel quite challenged, intrigued or provoked (in a good way) for it to be worthy of writing down.