How can I make a more perfect search and replace, that replaces only words surrounded by white space or by a punctuation mark or marks?

Use \b, that matches null strings at word boundaries. It's described in perlre, but has examples in perlretut:

An anchor useful in basic regexps is the word anchor "\b". This matches a boundary between a word character and a non-word character "\w\W" or "\W\w":

    $x = "Housecat catenates house and cat";
    $x =~ /cat/;    # matches cat in 'housecat'
    $x =~ /\bcat/;  # matches cat in 'catenates'
    $x =~ /cat\b/;  # matches cat in 'housecat'
    $x =~ /\bcat\b/;  # matches 'cat' at end of string
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Note in the last example, the end of the string is considered a word boundary.

44696420796F7520732F2F2F65206F
7220756E7061636B3F202F6D736720
6D6521203A29202D2D204A75657264