local plugins not showing up NopCommerce 4.2 (fresh clean install!)

Anyone know how to force NopCommerce to show the list of plugins pre-installed with NopCommerce 4.2 ?  I've rebuilt the solution twice to no avail (the database was created with default data and settings). The plugins show up in the plugins folder in the website, but will not show up in the Local plugins on the admin area, nor do they show up in the "All plugins and themes".
Clicking the [Reload list of plugins] buttons simply crashes the app (so this option is out).
Attempting [Upload a new plugin] also crashes the app.
Microsoft Visual Studio Community 2019
Version 16.4.2
What's the secret setting to make this work?

You seem to be having several issues with the source code version.  I recommend that you first install/run the no-source version.  After you download the archive, be sure to "Unblock" the file before you extract.   Run the app by dbl-clicking the Nop.Web.exe.