I have only used Wanikani to learn kanji and nothing else.
I have applied little of my knowledge, barely practicing or reading books that have basic Japanese grammar.
All I can do is understand a few words characters speak, as well as read some vocabulary and kanji, while being able to read hiragana and katakana pretty well. However, I have not been able to put my knowledge through the ringer.
I think I screwed up big time.
So â as they say, best time to plant a tree was 20 years ago. The second best time is now. Itâs generally true that itâs best to keep yourself more well rounded so you can get into really applying your Japanese, and itâs understandable to be a bit frustrated with your progress after this time. Iâd definitely recommend taking a look at resources for grammar, as well as ways to learn important commonly used vocab outside of Wanikani. Once youâve done that a bit, you can hopefully interact more meaningfully with media to learn from it.
That said⊠I need to preface this by insisting Iâm not trying to be rude and I only mean to help, but are you intentionally moving at the speed that you are? Or is it more of an accuracy issue? I know people have very busy lives and canât stop everything for Japanese, and picking a pace that works for you IS good, but depending on the level in Japanese you want to reach, there are limits where Iâd worry about being potentially too slow. Assuming you do mean a whole year, moving at basically one level per month puts you at 5 years to complete Wanikani. And that might be fine if you were doing more Japanese studying along with it, but⊠thereâs no getting around the absolute enormity of learning this language. The hard truth is that I think you might need to consider if you have more time to devote to Japanese generally or otherwise strategize how to be a bit more efficient as you broaden your studies, because I worry that the amount of years itâs going to take for you to really see fruits of your efforts is going to be an amount that is very hard for most people to stick with.
People who need to take it slower have my total support, but this is a gargantuan task in, just, total number of things you need to learn. I donât mean to pile on more negativity when youâre already concerned â just, this is a good opportunity while you are rethinking your whole study method to ensure youâre, as much as you can, giving it the time it needs (and prepared for how much thatâs going to be, heh).
Donât bring yourself down too much! The first step is to realize you made a mistake, so now you can work on reversing it.
On the bright side, youâre at level 12, so youâve been exposed to (edit: I counted properly this time!) 425 kanji. Thatâs more than whatâs covered in the two Genki textbooks (317) which is about 2 years of Japanese study at a university. Not bad considering you reached your current level in a year! Itâs more than enough to get your feet wet and get started with a textbook or work through more basic reading practice via a graded reader. Even if you only remembered half, thatâs still more than the equivalent of what you get in one Genki textbook.
How much Japanese grammar do you know? If little to none, thatâs no problem! Some people will use videos on Youtube to learn grammar, others will use textbooks. I donât know about the other textbooks, but I like Genki because youâre following the story of a foreign exchange student in Japan and her dialogue exchanges with different people in different situations. And in those dialogue sections, youâre introduced to a new grammar point (as well as vocab and kanji), and theyâre explained pretty well I think. At your level too, you shouldâve learned most of the Genki kanji that it covers.
If youâre lacking the motivation to move away from WK, try joining one of the book clubs like the (Absolute) Beginner Book Club. Thereâs also read every day challenge, extensive listening challenge, etc. where you can help stay accountable for your studies by posting for all to see!
Psst, this is a helpful post, I donât mean to nitpick, but I think you mean something like vocab or total items? WK only has a bit over 2000 kanji total. I just donât want to mislead them!
No, no youâre right! I was reading my little fuel gage thing wrong and looking at the incomplete kanji so far! Thanks for mentioning that! I honestly thought the number seemed oddly high when I typed it out too, but all logistics go out the window when you hear baby crying! 
Even if you think you screwed up, youâll eventually find that a year is not that big of a deal. 
I donât think youâve screwed up. I mean how much do you know now that you didnât know a year ago?! A lot. A massive amount. Donât say youâve screwed up big time, I donât think thatâs true at all. Youâve learnt masses.
I mean I do say this because Iâm pretty much in the same position as you 
Itâs because I donât find much time (energy) to sit over a textbook. But now I feel in a really good position to try reading things. Now I donât have to sweat over all the kanji as well as trying to figure out the grammar as well! Thatâs got to be a good thing. Imagine going at it with no background at all. You see youâve not been wasting your time. Youâve been putting in the preparation. Youâve got the rest of your life to read things and improve at Japanese.
Have you tried the tadoku books or Crystal Hunters, or some of the things in this thread?
Have you?
Or have you built a foundation for reading practice?
Because Iâm leaning towards the latter. You havenât screwed up, youâve just come to the realisation that your knowledge is unbalanced. You know how to fix this - learn more vocab, learn grammar, and read.
You absolutely didnât screw up big time. Youâre learning.
You might feel and think differently, but you havenât screwed up.
They advertise it as learning all the kanji in one year, but thatâs for a select few of people. Most either quit or spend multiple years.
So if youâve been sticking to it after one year, that is dedication and good work. Donât stare blindly at the results, look at where you were and how you are now. Itâs a bit hard to gauge where you are at that point, but youâve learned plenty of kanji where you can pick up a beginning grammar textbook and see them back. Keep moving forward, with a small step at it every time and youâll improve a lot.
My first year of learning Japanese, I did a year of evening classes where we learnt no kanji at all and I wasnât really confident with katakana by the end of it and when I watched japanese tv Iâd be lucky if I understood one word even with the english subtitles on. Seriously, youâre fine.
Iâm in the same boat, but spent 12hrs a day for 9 months and barely know whatâs going on in anime. If I use japanese subtitles however I get the gist of it.
Youâre probably not putting in enough effort.
Just trying to make sure Iâm reading this right. No typos?
What typos?
I feel the same way with pronunciation.
All hope is not lost!!
Youâre not alone, i started fully dedicated to WaniKani from September 2020 and starting level 4, iâm currently at 44, itâs quite bizarre that i know almost all N2 Kanji and can recognize most of them in lyrics, on the web, still i havenât touched grammar and itâs noticeable, because i can read but it doesnât make much sense a lot of the times because of grammar, being a different structure than english/spanish, having chosen to be dedicated to the Krabigator i might take WaniKani a bit lighter and focus more on grammar.
TLDR: Iâm the same but at level 44, must balance WaniKani with quite a lot of grammar to get to my kanji reading level (~N2)
Wow level 44 and I see this is your first time posting in the community! Welcome
Spending 12 hours a day studying for 9 months
Probably a bit more than that, was a cautious estimate. From I wake up to when I fall asleep (usually reading). Much of it is consuming content though.
I started putting into practice my reading only in lvl 11 with nhk easy news
and only recently lvl 33 in WK i started studying grammar with bunpro
I think every study need steps, so when I felt I needed something else, I went that path.
Also I listen to short podcasts (5min tops) every other day.
My next big step would be to read manga all in japanese, but since I confuse kanji all the time, I would mess big time trying to read without yomichan 
I quit learning Japanese for many years entirely if you want to talk about âscrewing up big timeâ.
But here we are now in 2022, and the only way is forward. Time to break out the old Genki 1.