The Vedic scriptures are indeed vast so vast we cannot estimate the beginning and end of it. One reason for its vastness is to do with the myriad nature of this world, in other words, there are so many varieties of people in the combination of three modes that one size does not fit all. Therefore the Vedas is but a reflection of this diversity and variety of this world and its people.
A self-realized soul or atmatattva darshis may not know all intricacies of Vedas, in fact is not needed to know. They only know the essence or saransham of the Vedas. If we want to understand the inner meaning of the vast body of knowledge, (a) we should have pure motivation (b) we should seek the appropriate spiritual master (c) we should in all humility surrender to that spiritual master. Once we do these three steps, the inner import, and essence of the Vedas will be revealed from within our own heart.
Yet, Srila Prabhupada very much wanted for his books to be distributed far and wide. The purpose for this is to make available to people genuine spiritual knowledge (gnana) and with that knowledge people are inspired to come to the stage of practice (vignana) which entails the three steps I mentioned above.
Unless we practice what we read (both external practice and internal introspection); we cannot 'realize' ourselves atmatattva, it simply will be like licking the outside of a honey bottle. Therefore gnana+vignana will reveal within us the essence or inner import of the Vedas.
yasya deve parā bhaktir
yathā deve tathā gurau
tasyaite kathitā hy arthāḥ
Only unto those great souls who have implicit faith in both the Lord and the spiritual master are all the imports of Vedic knowledge automatically revealed - Yajur Veda - Śvetāśvatara Upaniṣad 6.23