Using your code, I can see that external link is removed :
Before removeWordContent
array:3 [â–¼ "elements" => DOMNodeList {#2377 â–¶} "length" => 1 "query" => "//w:drawing[.//@r:link]" ]
After removeWordContent
array:3 [â–¼ "elements" => DOMNodeList {#2535 â–¶} "length" => 0 "query" => "//w:drawing[.//@r:link]" ]
but after saving, the final document has no longer the image as expected, but it still containing the external link in "word\_rels\document.xml.rels" and the Indexer is throwing a warning.
<Relationships xmlns="http://schemas.openxmlformats.org/package/2006/relationships"><Relationship Id="rId8" Type="http://schemas.openxmlformats.org/officeDocument/2006/relationships/image" Target="file:///\\SVFHVA\Commun\.......