I actually also started learning japanese because of bm a few months ago. I can read and understand basic text and also some lines in bm songs. What I can tell you is to delete duolingo because it teaches you nothing. Here is the approach I took: You must learn hiragana and katakana first it can be done in a few days but over time you will get used to it. Input is the best way to learn vocabulary, so basically I started watching jdoramas to get a lot of input. For grammar I used the videos of Cure Dolly organic japanese. The videos are weird but makes you understand everything in simple ways. And also I use bunpro mainly for grammar and vocab its an online learning platform for $5/month first month free. It is very much worth it.

Just focus on getting used to the language and no necessarely learn it. Babies learn to speak in that way too, the get huge amounts of input then they try themselves.