Fortunately in English classes (I learned English at school) we read Macbeth. There's a lot of layers to Shakespeare - for example a lot of allusions which you'll only understand when you know about the time it was written in. And our English teacher dragged in a native speaker to help out with conversation, who was a student living in my town.

In German (my native language) however, we were presented a poem without not enough context about the author and had to answer "what's the meaning of this". Most of the German teachers I had were boring, lazy or both.

Your literature problem - I had that in German, Thomas Mann's "Der Tod in Venedig". Yeah, I as a teenager was so eager to read about the homoerotic thoughts of an older man traveling to Venice and lusting about a young boy. Yes, of course it's symbolic but - fuuuuck me, really? Do I need to read that.

Mark Twain has written an essay about the "awful German Language" (I don't agree). Amongst other things he complained about long sentences.

Ha! He know NOTHING! He had not seen the works of Thomas Mann. Thomas Mann must have been hugely intelligent. He managed to write a single sentence that is too long for a single fucking book page. With a random number of subclauses in between. Exploiting all the cleartext encryption mechanisms the German language allows! With the most boring content a teenager in the height of puberty can not relate to.

I still have a visceral hate for Thomas Mann. In my 40s I thought I'd give that book another chance. Nope. Still hate it.

Ah, soon I'm 40 years past school and I still get PTSD about it.