Your sample document does not match the criteria required by the macro(s) I posted.
You have the bookmarks at the starts of the segments and not at the ends, and you have a column break(?) to separate each page, which was completely unexpected. To deal with that sort of layout you need a different approach.
Provided your actual document reflects the sample, the following will work. The sample creates four PDF files named with the bookmark names in the same folder as the document.
Code:
Sub Splitter3()
' 'Graham Mayor - http://www.gmayor.com - Last updated - 06 Oct 2018
' to split example document to separate PDF files
Dim strName As String
Dim oDoc As Document
Dim oTempDoc As Document
Dim oRng As Range, oPage As Range
Dim strPath As String
Set oDoc = ActiveDocument
oDoc.Save
strPath = oDoc.path & "\"
Set oPage = oDoc.Range
With oPage.Find
Do While .Execute(FindText:="^n")
Set oRng = oDoc.Range
oRng.End = oPage.End
oPage.Text = ""
Set oTempDoc = Documents.Add(oDoc.FullName)
oTempDoc.Range.FormattedText = oRng.FormattedText
strName = oTempDoc.Bookmarks(1).Name & ".pdf"
oTempDoc.ExportAsFixedFormat _
OutputFileName:=strPath & strName, _
ExportFormat:=wdExportFormatPDF, _
OptimizeFor:=wdExportOptimizeForPrint, _
CreateBookmarks:=wdExportCreateWordBookmarks, _
DocStructureTags:=True, _
BitmapMissingFonts:=True
oRng.Text = ""
oTempDoc.Close wdDoNotSaveChanges
Loop
End With
strName = oDoc.Bookmarks(1).Name & ".pdf"
oDoc.ExportAsFixedFormat _
OutputFileName:=strPath & strName, _
ExportFormat:=wdExportFormatPDF, _
OptimizeFor:=wdExportOptimizeForPrint, _
CreateBookmarks:=wdExportCreateWordBookmarks, _
DocStructureTags:=True, _
BitmapMissingFonts:=True
oDoc.Close wdDoNotSaveChanges
lbl_Exit:
Set oDoc = Nothing
Set oTempDoc = Nothing
Set oRng = Nothing
Set oPage = Nothing
Exit Sub
End Sub