ServiceStack и AWS: создал пустой проект ASP.NET, но не может выбрать .NET Core в целевой структуре

Я запустил проект ServiceStack ASP.NET Empty в VS2019, так как это было самое близкое к тому, что я хотел найти. Шаблон работает правильно, но я хочу запустить его в .NET Core.

Однако Target Framework был установлен на .NET Framework 4.5, но я хотел, чтобы он был .NET Core 2.1+, и я также не могу выбрать его:

Я знаю, что у меня установлен .NET Core, потому что я разрабатывал приложение Blazor также в VS2019, то есть .NET Core.

Я хотел бы знать, что мне здесь не хватает.

Редактировать

Вот файл csproj для проекта, содержащий AppHost.cs

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    <DebugType>full</DebugType>
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    <DefineConstants>DEBUG;TRACE</DefineConstants>
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