Tests won't run and projects won't build with VisualStudio 2019, or dotnet 3.1.x.

For example, right-clicking the ProductName_JustRight test and running it as instructed in the Arrays: Discarding and Populating An Array video yields:
"Could not load file or assembly 'file:///...AcmeApp\Tests\Acme.BizTests\bin\Debug\Acme.BizTests.dll' or one of its dependencies. Operation is not supported."
And if you navigate to that folder, the DLL is there so it's not clear what dependency is missing. Regardless, the tests won't run so the video can't be followed properly.

Other instances later in the video set, as seen in the attached screenshot, return much more complicated errors about how a container is missing.

Does anyone has any idea about the fix for the following warning (Environment BC17):
Method 'CreateWebService' is marked for removal. Reason: Method scope will be moved down to On-Prem. This function does not work in SaaS.. Tag: 16.0.

The compiler doesn't give any other information about the alternative for this function.

The current version of the application is completely unusable in new incarnation of the .NET. Trying to convert it manually is a nostarter, and all the tools I tried today are pretty useless.