When Dynamo is started, the Samples box on the homepage refers to the wrong folder.
It looks like it is not recognizing the language because it refers to the folder:
I can see it displays the folder C:\ProgramData\Autodesk\RVT 2020\Dynamo\samples
with all language folders inside, rather than recognizing the version and displaying C:\ProgramData\Autodesk\RVT 2020\Dynamo\samples\en-US
Dynamo 2.3.0, Revit 2020