I always recommend yomitan and Anki to other intermediate Japanese learners, and if they try it they love it, but they only try it if I set it up for them.

I combined an epub reader with a Japanese text parser and dictionary so that tap-to-lookup a word works with no setup. Then I added flash card creation and spaced repetition reviews. And a built-in 'explain' button that asks an LLM to translate and explain the grammar for a sentence. You can also ask follow-up questions after that.

I know it's all stuff that exists already, but I hope putting it together will make it more accessible to people, because this is really the method that got me to pass N2 without grinding practice tests. Happy to hear any feedback, and if you want to test out an app build just lmk!