Been slacking for a couple months after moving and being busy with work

First things first, you need to tackle your reviews to get them under control. I recommend making a study plan, based on the amount of free time that you have at your disposal. If possible, try to spend extra time on WaniKani, until your reviews are back to normal. It kind of goes without saying, but ignore new Lessons for now. Instead, measure your progress based on the number of items at Apprentice level. A good goal to aim for is getting to under 100 in Apprentice, since this will mean you have significantly fewer items coming up for review in the near future and things should be back to being manageable - but feel free to adjust that goal, based on personal preference.

Personally, I recommend using Reorder userscript, as long as you can trust yourself to use it responsibly. Wanikani Reorder Ultimate [old version, not working] When I have a large number of reviews, I will use Reorder Ultimate to chop the review up into smaller chunks - so I’ll focus on doing the vocabulary first. Then tackle the kanji, then the radicals. Or chop up the lessons based on review level - so I’ll start with the early levels if I’m trying to get clean up my Apprentice items, or focus on the more recent levels if I’m trying to move through the level a little faster.

The key to using Reorder responsibly is to NOT use it as a way to completely avoid doing the stuff you don’t want to do. Rather, just use it as a way to temporarily control when and how you review the material. With 400 pending reviews, you could use Reorder Ultimate to limit yourself down to just level 1 kanji and radicals that are due for review. Finish all of those, then move on to Level 1 vocabulary. Then do the reviews on level 2 kanji and radicals … and so on. Until you have done a comprehensive level-by-level review of all the pending material. Hopefully, this will also improve your recall and retention level, since you will be seeing similar material which might help trigger your memory and increase your correct responses.

I also use a Double-check/Ignore userscript for those times when I make a stupid typo or write the kanji meaning for the radical, but understand the item well enough to not want to see it again. Some people disagree with using Ignore scripts because it undermines the SRS timing. It is tempting to hit Ignore even when you should not. Use at your own risk.

On the subject of userscripts, if you don’t have one already, I strongly recommend installing a leech trainer, like this one. [Unsupported] Leech training script

This simple add-on lets you focus your attention on the items that are giving you the most trouble without worrying about making a mistake. The ones that keep coming back again and again, sucking away your time. It probably won’t help much right now, while you are dealing with a backlog of reviews, but it will be invaluable as you continue by letting you keep tabs on potential leeches and give them the extra attention they need so they won’t come creeping back into your reviews over and over. This makes a huge difference in keeping your Apprentice items down.