Comment by JamesNK

Here you go:

  <Project Sdk="Microsoft.NET.Sdk">
  
    <PropertyGroup>
      <TargetFramework>net6.0</TargetFramework>
      <Nullable>enable</Nullable>
      <ImplicitUsings>enable</ImplicitUsings>
      <OutputType>exe</OutputType>
    </PropertyGroup>
  
    <ItemGroup>
      <FrameworkReference Include="Microsoft.AspNetCore.App" />
    </ItemGroup>
  
  </Project>

Just create an empty ASP.NET Core project, change the SDK, add a FrameworkReference and a OutputType.

Read the console args and configure the web app with a port as desired.