There's no way to delete it, but password recovery being broken again is new to me, you should report that on discord where the site owner checks in once in a while. Moderation doesn't have access to the code to fix bugs or add features so we're stuck waiting for someone to report it (regular users rarely ever need this feature so whenever it breaks it takes a while for us to notice), then waiting for Puru to notice and fix it.
I don't remember if it was the case with the old Pururin, but I'm fairly certain the revived Pururin has never had the option for people to delete their accounts because there's no real good reason for it, people who want to leave the site can just abandon their account, people who think they can clear the tracks of some questionable internet activity that way fail to realise that their ISP and potentially government agencies already have that shit saved regardless of having an account here or not and people who want to re-create their account for stuff like this would be better of with a fix to the password change/recovery system as that would allow them to keep their favorites, tag blacklist, ect.