My experience with Italian was quite good:
My tests were good, because they were testing comprehension, instead of grammar theory. Not sure, if your test tested such things, but grammar theory is hard to know, if you don’t study it.
Being able to read academic books, as you said, doesn’t really prepare you for being able understand beginner or intermediate texts and conversations. If you want to do better in these lower exams, you need to be familiar with more conversational phrases and beginner vocabulary. Personally, for Italian, I studied lots of beginner content and then YouTube videos.