I'm following the official Get Started->Install guide on the Avalonia website, and it tells me to run:
dotnet new install Avalonia.Templates
dotnet new install Avalonia.Templates
This gives several complaints about "It is only possible to use this template with SDK-style projects". The full output of this command can be seen here: https://pastebin.com/9xMgCran
Then I'm told, "To list the installed templates run
dotnet new list
dotnet new list
". According to the guide I should see these templates: