Another welcome to the forum post, even though belated one
You appear to be on a really good path. To some of your doubts: Harry Potter is a common good choice for people who like it, have read the books previously and enjoy rereading them. An advantage over many other books is the usual quality of the translation. Basically, the publishers and translators do not often dare to mess up international bestsellers like HP or the LotR, which cannot be said about many other books. Yes, the later books are more fun, my personal favourite is the 5. I must say I wasn't too thrilled about the French translation of the Philosopher's stone years ago, but I loved the Spanish translations of books 5,6 and 7 last year. If you dislike the HP books in general, I'd say there would be little point in forcing yourself to read them.
There are alternatives. Some very good authors of teenage aimed fantasy and historical fiction books are Erik l'Homme and Evelyne Brisou-Pellen. They are intermediate friendly, quite enjoyable for an adult as well, and contain lots of useful, everyday French. Another good way to start are BDs (comic books), which include all the genres. There is much more to try than just the awesome Asterix. There are even non fiction BDs! As far as the translations go, I really found useful the translation of the Sookie Stackhouse novels by Charlaine Harris. I know it is not everyone's cup of tea (and I don't plan to go any further into the genre than this one author myself), but the language is very intermediate friendly and really ressembles the normal speech. But you don't need to go for any translation, if you don't want to, there is a lot of original French literature to choose from even at the beginning of reading.
Non fiction books and movie documentaries are awesome for the intermediates, even though you might need to switch to some fiction later, as the fiction contains a bit more complex language, more similar to the language people speak. After all, you have already found this out apparently. But some non-fiction tends to be more of a challenge, especially books on history and some other humanities. Philosophy texts are a [s]hell[/s] challenge
You might as well like to start watching tvseries, as those have been the key component for several French learners in this community, who have achieved high levels in the language. However, you might really want to consider the translations (good quality dubbings) this time as most French series are quite hard. I found Eureka excellent, Emk swears by Buffy the Vampire Slayer (I really recommend his logs!), there are many others. Later on, there are tons of awesome original French series. Should you want to go for an original series right away, some of the crime series are not that hard, such as Profilage, or some of the less original ones (really, the French have crime series of every kind and difficulty I can imagine). You mentioned videos on Netflix, now that I read your posts again. What series have you been watching?
And... Would you like to be my penpal?