If I could just give one piece of advice to my former self or other people earlier on in their study journey?
Dont start making plans how quickly you will reach a certain amount of grammar or kanji or vocab amount knowledge if you keep up your current pace and pressure/stress yourself that way.
Language is organic and real life exists so there will always be times you have less time or motivation and studying a language should be fun. Especially considering that really getting super good in Japanese will take a loooong time and there is no need to rush yourself.
Have been there with Kanji and with new vocabs a day or even new grammar a week before and in the end after a few months it just got annoying and just building those things around immersion/what you really want to do makes much more sense.
People probably say this often enough but never be scared of immersing too early. In times of the internet there is literally 0 reason to worry about finding stuff. And making mistakes helps improvement and comprehension anyways. Even if you only understand half of it, reading NHK easy with lookups or watching some streamer play a game or trying to puzzle together some lyrics is usually far more fun and motivating and you will look up stuff you come across anyways.
Could I have been 1000 times more efficient in learning Japanese than I ended up being? Yes. Would I really have kept up with the “perfect” method or while focusing on “numbers”? Probably not (as I already took multiple shorter and longer breaks over the last decade which I told myself I would certainly never need nor take lol).
So ye, long story short - dont worry too much about what stuff you gotta learn and how fast you are progressing and think you can keep all of that up, instead try out plenty stuff and balance the “study” part around it - as long as you do “something” with or in Japanese you will progress over time no matter what 
This was probably more than one bit of advice <.< But it all builds upon another, so I figure this still is okay for this topic 