Extra Study (other than WaniKani)

If you want to practice handwriting kanji, there’s https://kanji.sh/write/collection/wanikani It shows each kanji’s stroke order and has boxes to practice. I use it for each new kanji, and I repeat the mnemonic in my head and focus on the radicals while writing the kanji out. It helps with differentiating between similar kanji like 動 and 働. I do think this is sustainable to level 60, as long as you don’t dedicate too much time to it. But if you do want to go deeper into handwriting, Ringotan is a kanji writing app that incorporates srs.

As for what else you can do at this point: (I’m assuming you’re a beginner)
Grammar: there are plenty of grammar sources: physical textbooks like Genki and MNN, an online textbook like Tae Kim, youtube series like Cure Dolly, or and online source like MaruMori or Lingodeer. Whatever source you choose (and you only need one) stick with until the end.
Reading: at this point you can read graded readers, or something from the ABBC.
Listening: a good grammar source will incorporate listening, but you can also add a beginners podcast like Nihongo Con Teppei’s beginner podcast
Writing: the japanese sentence a day challenge was where I first started writing. Again, a good grammar source will include writing practice.