For my experience, I read Spring In Action 4 and 5, Getting Started with Spring Framework covering 5 and Dominik Cebula' tutorial on Udemy.
Dominik has already published 7 modules and he is working on the 8th module.
Reading Iuliana's book is also helpful.
Ivan's notes is also helpful
https://www.ivankrizsan.se/
For mock exam, I bought itestjava , certification-questions.
If you have an Android tablet, you may consider to install Spring Quiz Practice Exam for free.