Horses for courses...
PPL material for PPL...
ATPL material for ATPL...
Always best to master the basics first - laying good foundations and all that.
Too many people struggle with ATPL study, not just because of the quantity of material which needs to be learned (some of it unnecessarily, some would say...) but because they really haven't mastered (or even understood) the basics.
As a final comment, would you rock up to a rally driver's course to learn to drive a car, without ever having had a single lesson? Of course not - it would be a complete waste of everybody's time.