My personal notes are in obsidian.md and I basically go chapter by chapter. Bullet pointing things that stand out, then I write a recap of each chapter.

So it'll be

Chapter 1 -note -note -note

Summary

In this chapter we covered x and x is a word of contrasts.

I also make separate large pages for any topics that get expanded upon and link to those, like if it's a historic figure like Napoleon that will show up on another book I'm going to read.