In short there is no shortcut to reading.
What you experience is lacking all the skills you did not practice yet (sentence parsing, context inference, ability to tolerate ambiguity etc).
Reading will be painful deciphering for a long time but it get easier with practice.
In case you did not already read it: Joining the Absolute Beginner Book Club: Preparation and First Reading Experience Expectations
Like you graded readers just don’t do it for me so I’m working with what I like.
I’m very slowing going through ひぐらしのなく頃に 第一話 鬼隠し編 上 | L33 the process is to prepare the text enough to have the necessary vocab to go page after page. In the first 6 months this represent a bit more than 21/328 novel pages but I already got 49.66% of the total kanji needed to read the book and am just shy of 24% of the total vocab.
What I would do in your place if you can tolerate it is to work on your sumo book as primary material and do the same thing.
Extract the text, learn the needed vocab and kanji (I documented here a step-by-step process to have a custom JPDB SRS deck) for the small next milestone (start with one or two sentence a day and then scale accordingly) and then get to it.
It is long, painful and wonderful.
The good bit is that it won’t get harder ever because you will already be working on your final goal and week after week you’ll be able to see how easier it is to progress.
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edit: more stuff with an example analysis
Something that helped me a lot was to update my SRS practice and to ALWAYS parse a sentence for each term like the process will be
- Do i understand all the sentence intuitively ? (nope)
- What is the gist of it ?
I recognize 容 as (form, contains, look)
疑 (doubt, distrust, suspicion)
者 (person)
は
黒人 (black person)
の
男性 (man | gender)
だ。
So from this i understand that the sentence is roughly
(容疑者)(topic maker)(a black male)(is)
From this my guess was that “容疑者” was a “police inspector” (person who mistrust)
… turn out i’m wrong it was “suspect” but that not important what is important is that the unknown part was reduced significanly.
If you do that a thousand times you’ll see that you can infer the context of a LOT of sentences (and you start to recognize sentences and grammar pattern).
Not gonna lie the first hundreds of sentences are extremely painful. But this is what reading is and every thousand sentences trains your brain to do it better, faster stronger