I have good news. I did a big "cleanup" and now the nupkg generated by Visual Studio 2019 (right-click pack) is installing and working correctly.
Unfortunately I'm not sure which step fixed things. I cleared the NuGet cache, I toggled some options in VS Tools > Options > NuGet, I renamed and moved files, rebooted, etc. Suddenly the nupkg install added all the gRPC packages and their child packages to the target and it all works. Perhaps it was clearing the cache, I dunno. I have learnt that manually creating the package with nuget pack does NOT work. I get a nupkg file which doesn't install any dependencies given version=v0.0 It also gives the NU5182 error that I just cannot understand or overcome. Pack from the VS solution explorer generates a valid working nupkg. The way you pick the <icon> is not obvious, you place the PNG in the root of the project then pick it with a file picker and it just gets magically added to the root of the package. I haven't found a way of adding the PDB debugging symbols to the package via VS pack. *GK*
