Extensive and knowledgeable means reading widely and being well informed; Less but better means reading less, but you should really understand every book.

From a wide range of knowledge, it is broad and well-informed; From the perspective of understanding, it is less but better. But the combination of the two will be the best, with more knowledge and accurate understanding.

But reading a lot of books without understanding its meaning is tantamount to reading in vain; And those good books, which are few in number but understand every word, have a good effect. If you blindly read the book of 10 and don't understand its meaning, it is better to read the book of 1 word by word and understand it in place.

Therefore, personally, it is better to have fewer but better. If you don't think so, that's your own opinion. Everyone will be different, so you can listen to the opinions of the public.