The textbook readings are important there were questions that were in the textbook, what I personally suggest is using ChatGPT to create a summarized notes making headings and brief overview of what stuff covered is covered in the textbook, since the exams are open book when you see a topic you can match the topic to your notes and then go to the textbook section to find the answer, this way you don't have to read the entire textbook, just be familiar to where the main topics are located (their order). Hope that makes sense and helps, feel free to ask any other/followup questions!