No. I make one pass ... removeInvalidChars

Um,

sub XML::LibXML::Node::toSanitaryString {
    my( $node ) = @_;
    return 'XML::LibXML'->new( qw/ recover 2 / )
        ->load_xml(string => $node->toString )->toString;
}
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All that is left is to supress the "xmlEscapeEntities : char out of range" warning toSanitaryString generates