Things will definitely get crazy, but I would suggest not resetting. I reset recently, but not because I had too many reviews. For me, it was because I’d taken an unexpectedly long hiatus and ended up forgetting most of my most recent levels. When I have a looooot of reviews to get through, I like to use the WaniKani Reorder Ultimate script to break everything into more manageable pieces! I’ll generally right-click and remove all but one level (unless the lower levels have so few it makes sense to just keep them together) and then just do the reviews level by level.
It’s nice having them separated by the script because there’s an end in sight! After you finish each level, you’ll be taken to the summary page and told you still have reviews available. Everything can be broken down in to manageable chunks, and who knows! You might be able to finish it all in one sitting, motivated by your success at finishing each level to tackle the next one! Good luck c: