That link does not work for many non Northern American users.
In general you need to go to your ( = the country where your switch came from) countries' nintendo website.
E.g. for a Dutch switch go to nintendo.nl
There are different sites for different countries. But in general you first need...
This is not always possible.
If you have no nintendo account coupled and lost the phone which was used with the app for setting it for instance. In that case the only option is to send it to nintendo for repairs (they do a complete reset). I have my doubts if they 'repair' a banned device...