I made a mistake when I started WK. I focused exclusively on WK. By Level 15, I was drenched in kanji, vocab, and radicals. I didn’t make time for the other parts of the language (I do understand a lot of spoken language but suck at speaking as all my Japanese consumption was watching Anime/J-Dramas and not actually thinking in Japanese).
Figure out a pace in WK that allows you to keep leveling up/learning Kanji, while adding in other parts of the language. You will need to understand spoken Japanese. Start watching Japanese programming with Japanese subtitles. Or watch in Japanese, no subtitles at all, and focus on listening. Put your phone away. Turn off your tablet. Your computer (unless you know, that’s how you are watching… in which case, turn off ALL notifcations and don’t get distracted with Instagramcracker, Fartbook, or any other thing that takes your focus off of LISTENING.
As @seanblue said, pick up a grammar book. Mix this into your language learning process. Build a schedule for each day if that helps you. Maybe Sun/Tue/Thur/Sat you do WaniKani. Mon/Wed/ mix it up. Monday do GENKI for a chapter or 2, and Wednesday, spend an hour or 3 watching RAW or Japanese subtitled (not English subtitled) content while focusing on it.
Or build a daily schedule that looks something like this:
8 AM - 9 AM = WaniKani time
10 AM - 11 AM = Japanese language YouTube with Japanese subs
1 PM - 2 PM = Read and work on GENKI
5 PM - 6 PM = Back to WaniKani
Something like that. Obviously you don’t have to do this exactly, but you need to start mixing up your learning and include all aspects. Technically as children we learn to speak by listening and don’t start reading until school age. Now you have the luxury of figuring out what you really want to focus on first. I still think speaking/listening is easier to start with as it allows you to “hear” what you are reading when you get to that step, but that’s not how everyone learns or wants to learn.
Whatever you do, don’t give up.