The bulk of any text is comprised of the most common 500-1000 words, making up roughly 80% of the text. Words such as “the”, “do”, “that”, “live”, “she”, etc. You need to learn these and understand them without thinking to be able to read a book. Cognates don’t really help you here too much, German and especially French share little core vocabulary with English. Usually you won’t reach this level before B2.

That being said, I did manage to slowly read quite a dense book about futurism back when I was between B1 and B2 level of German (with a dictionary in the other hand). Also, reading a book but not understanding everything is completely fine and a good way to learn a language.

Some types of books are easier. Comics might be your best bet, children’s books are easy too but I wouldn’t be too motivated to read them.