I followed other people’s method to be able to redeem the code.
Here are some things I did after I inserted the game into my console.
1. Change your console’s region to Europe in settings.
(to find the region setting just scroll to the end and there is a section for region.)
2. Go to the Nintendo Eshop and check your balance, I had $0 for the balance, and the coins you get from games don’t matter.
(only the first balance should be $0)
3. Go on a laptop or phone log into your Nintendo account in settings there change your region again to either Switzerland or another eligible European country that is noted on the back of one of the cards the game provided.
(The code is only redeemable to 4 European countries. I will include an image of the flags eligible.)
4. Then go back to Nintendo Eshop and log in again. Since changing the region on your account will log you out.
5. Lastly, redeem the code it should work!!!
(Also, just do the same steps to change your console and Nintendo account’s regions back to U.S.)
(It won’t interfere with the code since it was downloaded before the change. It will also ask you to enter your password again on the Nintendo Eshop since the region was reset again.)
(Another, thing I forgot to add was if the code was redeemed but not downloaded because you didn’t know which option to pick because of the language.)
(Go to your Nintendo Eshop icon on your console and click an option until u get the redownload section and the content should be there and just press download).
I tried to be as specific as possible.
Hopefully this helped!
:)