That’s completely normal. There’s a difference between recognition and production. Wanikani is pretty much all about recognition. You can use Kaniwani to practice the opposite (Using English keywords to recall the Japanese) but adding even more to the SRS pile can end up overwhelming, and your time might be better spent elsewhere. Like learning grammar.
Probably the best way is to simply try using Japanese to talk to others. You can try posting in the Japanese only section of the forums for practice. You’ll make mistakes at first, but actual use will help it stick better. You could also just put it off until much later if you don’t intend to be using Japanese to communicate with others.