I read Spring in Action 4th and 5th edition as well as Getting Started with Spring Framework 5.
Also, you may want to try Iuliana Cosmina's new study guide as promoted on this forum.
I heard there are some sample questions in her book.
I recommend you to take itestjava's mock exams. But mock exams are just for practice. The real exam is
harder than those mock exams.
You can also consider taking Dominik Cebula's Spring Professional Certification courses on Udemy.
A lot of students said his 8 courses are very helpful for them to pass the exam.