Hey. I checked out the Miitopia wiki and saw you tried contacting the admin/bureaucrats with the only success being that one of them replied to say they aren't interested anymore.
That means YOU could start the wiki adoption request right now if you want and (provided you've made some decent and regular edits for a week) probably be approved.
However, to ease the transition I will reach out to Jewel on Discord and see if they can look into whether they want to give you or another current editor of the Miitopia wiki Admin and/or Bureaucrat rights. This would mean you wouldn't even need to do a formal adoption request.