I’m sorry to hear that you have not been able to get a working Blazor MAUI app following this article. 
Unfortunately, it is based on .NET 7 and has not been updated to use the new Auth0 SDK, so I understand that it turns out to be very confusing in combination with the other articles.
There are plans to update this article, but right now I can’t say when that will happen.
I’ll ping you as soon as an updated version is published.
Sorry for the inconvenience and thanks for bringing this up 