I recently cleared AWS Devops Engineer Professional exam.
Below is what I did and hopefully can be helpful to you as well for the exam.
- Stephane Udemy course. I did everything he told. Readings (He suggests lots of things to read) + Watched videos 2 times and labs. I did all 3 Associate exams also following Stephane. So, he does assume that we know the basics.
- AWS Official Devops exam readiness. This course tells about how to approach the question and the test. I highly suggest you to take this and it is a free course.
- Whizlabs practice tests. My average was around 72% and 87% in the final exam.
- Udemy https://www.udemy.com/course/aws-certified-devops-engineer-professional-practice-exams-/. My average was around 70%
- AWS Official practice test. I scored only 60% in the practice test
This exam tests your time management. So keep an eye on the watch on your side. Try to finish 30 questions in first hour, 30 in second hour and 15 in the remaining time plus for the questions you marked for the review. I was very slow and managed to finish the exam only 5 mins to spare.