Though tempting, I think it’s not that easy to correlate to levels…
Learning vocab, kanji and grammar points are of course very useful, but what’s most likely to increase your ability to read is simply reading itself.
I started out reading books aimed at native speakers about two years ago, and at that time it was difficult for me to find material I could understand. Looking back at some of the things I was unable to read back then, I can see that they’re legible now.
While I certainly have been studying kanji, vocab and some additional grammar during that time, I don’t think these are what’s caused this change to happen.
You can technically know all the words and grammar points in a sentence and still fail to parse it since you also need experience decoding this in the context of a sentence aimed at a native speaker.
TLDR: basically, in order to improve your reading, start as soon as you can (WK, bunpro etc will certainly make that sooner!) and then make sure you keep reading 