I think you have fallen into a misunderstanding, equating the content of the textbook with the scope of the exam. There are many things in the textbook that are not tested, especially Math III. It is suggested that when reviewing textbooks, we should look at them according to the exam outline.

As for the textbook version, there is really no need to struggle. The knowledge needed to master the postgraduate mathematics has been concluded as early as hundreds of years ago. The new textbook mainly makes some adjustments to the examples and exercises, so you can use the existing old textbooks with confidence.