Are there ways to make academy classes more enjoyable?

The academy I work at seems to operate too much on a test-oriented basis, making it difficult for students to find the classes enjoyable. In particular, during multimedia class sessions, students are given activities where they fill in the blanks from a video script, which they find boring. This activity is not only an important part of the class but also a key element of the exam, so it's hard to omit or change it. Students will take a test where they listen to the audio review from the previous week and the vocabulary from the current class, and they have to write down the English spelling and Korean translation. Most students are not familiar with grammar, making these activities quite challenging. Additionally, many students did not choose to come to the academy on their own, so they lack motivation. Is there a way to make the classes more enjoyable? Due to exam preparation, there isn't much time for games, and while I occasionally reward them with candy, it doesn't seem to have a significant effect. I want to teach grammar more, but managing 15 students is quite difficult. I would like to hear your advice.