Exactly this, if you are at a level to understand most of the book in your target language then just carry on reading. I look up words only if they repeatedly come up in the past couple of pages and I’m still none the wiser so I quickly look it up. Even then, try not to look up a translation of the word, but look up the word in your target language so you get a definition, not a translation. My tip would also be to take your time. Initially, you might find that reading in your target language is slow and feels easy for your mind to wander and choose the path of least resistance… but keep at it and it goes get easier and starts to flow. You’re training your brain through native level exposure, so initially it will feel tough. Good luck!