No, no one has ever done this :P

Japanese can be difficult to native english speakers from what I hear but I don’t personally have experience enough with the language to tell you.

Generally I would say learning an entire language for the sake of consuming a specific media, especially a language not widely spoken outside of its country of origin, is a waste of time yes. At the very least, it is not usually motivating enough to get you to stick to learning that language long term.

However, I don’t mean to discourage you. Language learning is still fun and teaches you a lot about its culture of origin and their values. In my experience language learning apps like duolingo (especially duolingo these days) are not the way to go. Buy some textbooks, there are tons of japanese language learning youtubers who can point you to good ones, then go on some chat sites and practice what you are learning. Don’t just watch anime, listen to japanese music too, try to pick out what they are saying as you listen.