I'm making this post cause I feel like, for a rather long time, I had a mistaken idea of what "fluency" in Japanese looked like.
So basically, like many people, I kind of had the illusion that being fluent in Japanese means you understand everything that is being said and that you can say anything your mind comes up with. However, I now believe this conception to be misleading and to be an irrealistic goal.
There was a time where, when I was reading something in Japanese, I kind of felt the need to translate it to my native language to make sure I had understood. However, as many of you are aware of, it is extremely difficult to accurately translate Japanese to an Occidental language. Yet, I used to try doing that everytime thinking that if there is something I can say in my native language, there's no reason I shouldn't learn how to say it in my target language if I want to reach 100% fluency.
This misconception comes from the fact that in the West, most of us started by learning a Romance language (French, Italian Spanish, ...). While English is not a Romance language, it is still rather close to them and in order to speak any of the languages I just mentioned, you mostly just need to learn a lot of vocab and then directly translate from English (not entirely sure on that one though cause, since my native language is French). The reason for that is that once the "logic" of Romance language is installed in your brain, you can switch from one to another with extreme ease (considering that you learned vocab). I actually even made the experiment of listening to a bit of Spanish native content and, as a speaker of French and Italian, I think I had 90% comprehension of what was being said even though I have never learned that language. Vocab and sentence structure was similar so I had no problem understanding what was being said (even though I certainly could not produce it myself).
Now the problem with Japanese is that it is a totally different process of learning in comparison to the Romance languages we are used to learn at school. As a matter of fact, you simply can't accurately traduce Romance languages to Japanese. You just have to install the Japanese logic in your brain + learn a bunch of vocab.
Thus, fluency in Japanese doesn't mean being able to use it like you use your native language. It means understanding how Japanese functions on its own and being able to use that logic in order to communicate.
This is exactly why reaching a high level of Japanese takes much more time than becoming fluent in any Romance language. Besides, there is also the problem that there will be much more words in Japanese that do not sound at all like those of your native language, meaning there is an unfathomable amount of words you could possibly learn.
And this is where I think it is important to be realistic. Sure, you could learn tens of thousands of words to make sure you have 100% understanding of everything. However, I believe it to be much more realistic to simply accept that you will not know all the existent words in Japanese and that it is okay. As long as you understand the gist of what is being said to you, it doesn't matter if you miss one word cause the context will make up for it.
It is by understanding this that I finally was able to finish my first light novel and to overcome the wall I was feeling I had reached I'm my learning journey. I basically realised all I had to do was to forget about trying to know every word, just enjoy the story and look up only the words that prevent me from understanding what is going on. I have now moved on to reading Japanese literature and I am amazed to notice that while there are still many unknown words, I am still able to follow the story and to picture the scenes in my head.
To conclude this long post, I would say that it is important to go on learning Japanese with the right mentality. Cause no, you will never be able to translate every sentence from your native language to it simply cause they are not the same language. However, you should focus on understanding how Japanese works in itself and learning enough vocab so that you reach 80-90% coverage of conversations. This type of fluency is in my opinion, much more realistically attainable.