Sadly they’ll never fix this. Every other competing app that is not wanikani has timings work to the user, but wanikani has used the same system forever and punishes you the following day if you can’t do your reviews at the exact same time every single day.
I raised this thread and a thread before this year(s) ago All Reviews At X Time
But sadly both the wanikani admins don’t want it, AND you will receive push back from random users here against a basic feature every other SRS app has.