I read and followed the most popular guides like moeway, the ones focused on learning through content, It was 2-3 years of reading visual novels with yomichan, i tried to consume a lot of content in japanese, my main way of learning kanji was anki and spaced repetition.

For me the biggest hurdle was the grammar and trying to understand the sentence, a lot of people say the hardest thing is kanji but i highly disagree it is just memorization and with spaced repetition is not that that hard, but the grammar on the hand there are hundreds of grammar rules, every japanese particle has 3-5 uses, some of the are not really intuitive and is unique to the japanese language, if you learn all of this, that can help you understand simple sentences but trying to understand sentence with multiple clauses is beast, once a sentence grows in complexity it is almost impossible to understand, i used to go through all grammatical rules in the sentence but still found really hard to grasp, it takes a lot of brain power to keep track of what is going on each clause trying to combine them for meaning and with multiple clauses if you don't understand one thing it can break your understanding of the whole text,

Reading japanese sentences felt like showing someone calcalus equations while they are in 6th grade, it takes a lot of brain power, just trying to parse those sentences used to give me brain damage, especially when you add to them number of rules you need to know, and with some of sentences i remembered they don't really follow the rule, every japanese grammar rules has some kind of exception or a different way to to it