I've been finding that I'm coming up against the same frustrations as the author.
I'm reading a bunch of textbooks and adding notes as I go to anki. I find that so long as I'm equally as willing to _drop_ a card from anki, it works well. However if I focus too much on this then I lose the flow of just reading and absorbing.
I've also run into this frustration and come to the conclusion that for me, no learning style actually works except for putting what I've learned to use, and doing it quickly. Granted, that means I'll probably never become a doctor, but I cannot force myself to memorize and "learn" something that I am not using, but if I currently _need_ to know something in order to use it, learning and retaining it is natural and easy.
I've been doing this as well, but I specifically try to come up with good questions and add those. Usually at the time I add the question as a flashcard, I don't know the answer yet, so I leave that field blank. Later on every time the flash card shows up, I refine the answer and return to the textbook if necessary. I find that the effort required to come up with interesting questions is very beneficial to the learning process by itself.
I also sometimes include the name of the book and page numbers so I can quickly return to the relevant section.
I have been recently integrating Anki into my book reading. If you are willing to share your Anki cards on books there has been a relatively new subreddit that might interest you.
https://www.reddit.com/r/ankibookclub/
I'm reading a bunch of textbooks and adding notes as I go to anki. I find that so long as I'm equally as willing to _drop_ a card from anki, it works well. However if I focus too much on this then I lose the flow of just reading and absorbing.