Kanji/Vocab vs. Onyomi/Kunyomi

You don’t necessarily have to memorize whether a given reading is On or Kun when you first learn the kanji. Eventually you will get a feel for which readings are which as you learn vocab. For example, the On’yomi ニュウ for 入 is used in jukugo such as 入社, 入学, and 入所. Meanwhile, the Kun’yomi readings for 入 are taught in vocab with okurigana: 入る, 入れる, and 入り口. Tofugu made an article about On’yomi and Kun’yomi if you want more details. In the end, the most important part is being able to read vocabulary properly.

There are a few userscripts out there that you might be interested in to help distinguish On and Kun in your reviews. KunOn specifically tells you which reading WaniKani is looking for when you do reviews. Katakana Madness automatically replaces all On’yomi readings with katakana, both in reviews/lessons and on the dashboard. I think that these scripts provide good ways to passively learn On vs Kun without added stress.

Good luck in your studies!