> A useful habit that I've begun to follow with more complicated books—especially when reading them out of personal interest—is to actively avoid taking notes or worrying about background material on a first read.

I recommend using those little sticky tabs instead. If I come across something I want to look up later, or want to come back to for whatever reason I use one on the page itself to to highlight the line, and another at the top so I can find the page again. By the time I'm done reading it might be full of those little tabs but it doesn't really slow me down in the moment.