Anime for teenagers and adults generally uses more complex language. At least in my experience, this makes it very hard to get started. Kids shows, on the other hand, often use very simple forms, which makes it easier to get a grip on things. I try to see them as exercises, so I can get to the better shows that I want to be watching. Hopefully, someone else can prove me wrong. I, too, could use some recommendations that are not just kids' anime.

Do you have an example of a book that makes problems? I can try it on my e-book readers

I just use some Anki cards that I found online. Googling it, I found multiple Anki card decks for the Heisig method and I just chose the one that fitted me best.