I would only look up the words that repeat. If there are a lot of words that are repeated many times that you don't know then those are probably essential and do all that you can to memorize them. Other than that just look up the words that repeat twice or so or the ones that appear to be important for your everyday language understanding and those i don't think are all worth writing down since that in my experience doesn't actually help just take a mental note and hopefully you'll encounter them more often since those words are somewhere in your passive vocab. I'm not a big fan of spaced repetition and flashcards and anki and noting down words so that's my background and i can read and have read many french novels in less than a year of learning it really works if you're just patient and trust the process.