If you are not going to put it on nuget.org would you consider making a nuget package (nupkg) that is included in the standard download then? I can create a nuget.config file that points to a private repository. I do this with other vendors that don't ship public nupkg files.
With NuGet my project MyProj.Ftp.csproj can reference the NuGet package and anything that references MyProj.Ftp.csproj and the MyProj.Ftp.nuget package will be able to determine it depends on edtftpnetpro and get the dll through NuGet.
Without NuGet, I need to add a nuget reference MyProj.Ftp and then also add a reference to the edtftpnetpro.dll. It also gets messy when a project targets both net472 and netcore. Nothing that can't be done, just need to mess around with csproj references to the correct dll.
NuGet is the standard package manager in the .net world so it should be used.
Thank you for considering.