Ugh, I also struggle.

I'm learning French and the books I try to read are written for someone with at least a C1 in the language, and I merely have a B1. What helps me is reading the book in English first. You can read the translation in the language you're comfortable w. I also suggest ordering the e-book instead of a physical book from now on, if that's possible for you, since the e-readers have inbuilt dictionaries and some apps might also have a translation tool.

Keep a dictionary handy if you continue reading this book, but it's fine even if you don't wanna look up every difficult word you come across. I skip entire paragraphs when I'm not able to understand them, because it gets frustrating real quick if I try to look them all up.

I mostly read on my phone and it’s in French. I've also chosen French as the text-to-speech output language, so in case I need help with the pronunciation of a word, I can just get my phone to read the text aloud.