How to embed all dependent DLLs into a single EXE for SmartPlant P&ID automation using VB.NET?

You can add .Net assemblies as a resource and in the ApplicationEvents.vb file add a handler to resolve them to those resources

Namespace My
    ' The following events are available for MyApplication:
    ' Startup: Raised when the application starts, before the startup form is created.
    ' Shutdown: Raised after all application forms are closed.  This event is not raised if the application terminates abnormally.
    ' UnhandledException: Raised if the application encounters an unhandled exception.
    ' StartupNextInstance: Raised when launching a single-instance application and the application is already active. 
    ' NetworkAvailabilityChanged: Raised when the network connection is connected or disconnected.
    Partial Friend Class MyApplication
        Private Sub AppStart(ByVal sender As Object,
  ByVal e As Microsoft.VisualBasic.ApplicationServices.StartupEventArgs) Handles Me.Startup
            AddHandler AppDomain.CurrentDomain.AssemblyResolve, AddressOf ResolveAssemblies
        End Sub
        Private Function ResolveAssemblies(sender As Object, e As System.ResolveEventArgs) As Reflection.Assembly
            Dim desiredAssembly = New Reflection.AssemblyName(e.Name)
            If desiredAssembly.Name = "Ookii.Dialogs.WinForms" Then
                Return Reflection.Assembly.Load(My.Resources.OokiiDialogsWinForms) 'replace with your assembly's resource name
            Else
                Return Nothing
            End If
        End Function
    End Class
End Namespace

It is important to note this only works for .Net dlls