I’m not entirely sure if this is what you were looking for, but there is a user who have made a website “KaniWani” with the vocabs in reversered order:
https://kaniwani.com/auth/login/?next=/
There is also a thread about it :)
/t/Kaniwani-Major-Update-134/11634/1
AND more…
/t/Feelings-about-WaniKani-vs-KaniWani/7780/1
Even Koichi recommends it!