Save a worksheet off as it's own CSV without errors.

I am trying to get this code to work without errors and there is one error I cannot get past.

Sub EXPORT_CSV()
    Dim fPath As String
    Dim wb0 As Workbook
    
    With Application.FileDialog(msoFileDialogFolderPicker)
        .AllowMultiSelect = False
        .Show
        If .SelectedItems.Count > 0 Then
            fPath = .SelectedItems(1) & "\"
        Else
            Exit Sub
        End If
    End With
    
    fname = fPath & "my_file.csv"
    Worksheets("my_file.csv").Copy
    Set wb0 = ActiveWorkbook
    wb0.SaveAs fname
    wb0.Close
End Sub

So as long as you have a worksheet named "my_file.csv" then the code works great. It's when I go to open the saved worksheet that I get my first error.

The file you are trying to open, 'my_file.csv', is in a different format than specified by the file extension. Verify that the file is not corrupted and is from a trusted source before opening the file. Do you want to open the file now?

And I click yes and the file looks correct; I see the one worksheet with the exact same data on the workbook I saved it from.

Does anyone have any idea what is going on here? Thanks for your help.

Sub EXPORT_CSV()
    Dim fPath As String
    Dim wb0 As Workbook
    
    With Application.FileDialog(msoFileDialogFolderPicker)
        .AllowMultiSelect = False
        .Show
        If .SelectedItems.Count > 0 Then
            fPath = .SelectedItems(1) & "\"
        Else
            Exit Sub
        End If
    End With
    
    fname = fPath & "my_file.csv"
    Worksheets("my_file.csv").Copy
    ActiveWorkbook.SaveAs fname, FileFormat:= xlCSV
    ActiveWorkbook.Close
End Sub