It’s been six months, it might be better to reset. Getting rid of that backlog would be like getting a new level and learning 210+ kanji in one go with the vocabulary to go with it.
What’s more important is setting up a reliable schedule that you can stick to rather than draining your soul trying to get a handle on so many review items. The hardest thing in wk isn’t the kanji/vocab, it’s sticking to a realistic schedule lol.
Plus, you’re not in a race with anyone right? It’s your own personal goal, do it your way and those regrets you might have toss them aside and try again.
Personally I had to drop bunpro while doing wanikani. When I revisit bunpro in march or so, I know I have hundreds of reviews waiting for me, but I’m going to reset. It’s not about time, it’s about doing it right and on my own terms.