There are going to be other methods but the below works for me, it will open a specific pptx file, add a slide, paste the selected/ active chart to that slide.
You may need to either edit the binding or add a reference to the PowerPoint object library in the VBE.
Sub ExportChartsToPowerPoint()
Dim strPresPath As String
Dim ppApp As PowerPoint.Application
Dim myPres As PowerPoint.Presentation
Dim sc As Integer
strPresPath = "C:\Users\jbloggs\Desktop\test.pptx"
Set ppApp = CreateObject("PowerPoint.Application")
Set myPres = ppApp.Presentations.Open(strPresPath)
sc = myPres.Slides.Count + 1
With ActiveChart
.ChartArea.Copy
myPres.Slides.AddSlide sc, myPres.SlideMaster.CustomLayouts.Item(7)
myPres.Slides(sc).Select
ppApp.ActiveWindow.View.Paste
With myPres.Slides(sc).Shapes(1)
.Left = 100 ' Adjust the left position as needed
.Top = 100 ' Adjust the top position as needed
.Width = 400 ' Adjust the width as needed
.Height = 300 ' Adjust the height as needed
End With
End With
End Sub