I'm not a believer in highlighting, at least for myself, since what happens when I do it is that I accrue a series of things that I vaguely intend to come back to one day; and yet that day never comes, because there's always more to read.

What works better for me is to "read at the speed of synthesis" where I take a lot of notes in the course of reading, where "notes" really is: my reactions to things, digging into them, asking questions, etc. Then these notes get put into the rotation of things that I review periodically. (I have tools to help with this so the review actually happens.) This is much slower and thus serves as a rate-limiter of what I attempt to read.

The key is to know what it is you're after. I have read thousands of books that now, years later, I have only the illusion-of-knowing about. Since my goal is to engage with the book, and be changed by it, interactions that don't afford that are useless to me. It's just LARPing, bedpost-notching.

Not saying this is right for everyone, just what I do.