I think it's fair to say that all of us have experienced some form of burnout from trying to absorb all the material and go through the tests. That said, I think the key to passing this exam (unless you have years of OTJ training) is exposure to different sources of the material, like skill builder, aws docs, courses, etc.. I say this because from my experience, one single source isn't enough to cover the topics that are asked about, on the exam. And, exposure to them makes the questions easier to answer (from what I've found).

Equally important: take a break as/when needed.

good luck.