I remember reading someplace (I completely forget) that Mario Kart 8 for Wii U and Switch use completely different (or at lease just different enough so they won't work) file structure or format. So you can't just copy and paste them from the Wii U version. Even if you could (like I said above I...
i put in my birth year as 2000 instead of 2008 because i was sleep deprived as FUCK and had trouble reading it. I contacted the admins case that'z what it said.