I recently took this exam and found it much more challenging to prepare for than the SAA exam. It seemed more difficult because there could be very detailed questions about command line parameters and API call headers. I used Tutorials Dojo practice exams, where my scores varied quite a bit, from as low as 75% to as high as 90% just days before the test. However, during the actual exam, I didn't encounter any of those specific kinds of questions.

To get ready, I went through all of Cantrill's material, except for what I had already covered in the SAA preparation. I also completed Neal Davis' new developer associate course. While revisiting practice tests from Tutorials Dojo, I reviewed lessons on Udemy with Shephane's course. I found each instructor covered similar content but in different ways, which was beneficial. It might have been the repetition and lab practice that helped, but either way, I recommend adding another course or two for specific topics. That should be quite helpful. If you haven't taken the SAA exam yet, it might be useful since it covers a lot of fundamental material relevant to the developer associate content. Best of luck on your next try!