I agree wholeheartedly with the other users here, no outside engagement with things like grammar will make even the process of WK itself incredibly difficult and confusing. WK is great, but its exploration of conjugation, particles, structure, kana-only vocab, etc. is (by design) not its focus to the point of being nonexistent here. Everything in linguistic study supplements each other, so it’s best to vary the scope as you go through it.
As with any art form- language included- there is immense value to learning from varied resources, so I wouldn’t recommend all eggs in one basket. However, for something more gamified I’ve gotten a lot out of Busuu.com - it’s similar to Duolingo but with much better guidance and explanation of the concepts being explored, along with containing much better listening and writing practice, longer form reading, content variety, and even interaction with native speakers. It also has tests based on CEFR language levels that can help gauge progress.
I also think Tofugu has tons of valuable content, JLPT study guides can help see progress levels and standards to aim for, and Jisho.org is richly detailed for vocabulary and contextual assistance.
Beyond that though, I say explore any and all corners you can. Websites, forums, youtube videos, books (I know not keen on, but more manageable when one gear in a larger system rather than sole focus), etc. I’m sure people more equipped than I will give some specific suggestions, but widening your net in general will let you see all sorts of new perspectives and compare/contrast to emphasize key elements and those more expressive of individual voice- all which are useful. Any effort to diversify your experience will only serve to help you practice and grow, in my opinion.
The hardest part of learning a language, especially one as complex and nuanced as Japanese, is that it is a long process- and one with inevitable roadblocks. Even goals like “complete a course” are so large it can be overwhelming quickly no matter the intention and determination going in. Above all else, don’t strain yourself and find peace in a slow-burn. Bite-sized and very intentional goals make it much easier to stay committed, see tangible progress, and fit into schedules in a way that works for oneself. It’s a big undertaking, but one you should feel very proud for taking on at all. You’re doing great and will continue to do so as long as you stay determined and mindful.
Looking forward to seeing you grow, you got this !