I can’t pick just one option because it feels entirely dependent on someone’s goals and interest.
Say for example someone who’s mostly learning Japanese because they have a huge interest in sake. Then it wouldn’t make sense to tell them to read broadly; it would be better to focus a lot on the topic of sake.
But what if someone’s goal is related to reading broadly of Japanese literature. What if they want to understand the culture better? Then reading widely is precisely what they will need to do.
So saying that one is better than the other is impossible. It depends on your goals. It is a bit like saying that reading novels is better because the language is more complex and deep, while the person you told it to is only interested in reading manga.
We all have different goals, so take different approaches. And then it is also about interest.
If you look at me as an example, I will finish the last couple of Ask graded readers level 4 I have. But it isn’t because I necessarily think they will help me with Japanese, nor do I find most of the stories interesting. Part of my motivation is just: I own them. But they also touch on subjects and themes I don’t normally read. Also, I find that a lot of them are famous short stories or from famous authors, so there is value in reading that because it might enrich my reading in the future (since other works might reference them).
But I won’t get through them very quick because as I said, not very well suited to my taste. On the other hand, I just picked Sailormoon back up again and I happily read more pages after my update yesterday just because it is fun. I also have some other things I’m thinking of when I want to try read.
While those last two graded readers are like: well, I’ll get to them when I get to them, but I will read them.