How does on remove or damage unicode layer in PDF. format?

Pdfs consist of 2 layers one being unicode map the other gylph map. Unicode stores all kinds of information, the one that you use to copy and paste the text with and gylph is essentially the way the text looks, thus if you delete unicode or damage it somehow you will protect your file from being copied somewhere (excluding ocr) but the text in the file will still look the way it is supposed to. Just like in the picture below. So the question remains: how does one remove unicode in PDF in order to protect the file from being copied anywhere? Thank you for your input!Image may be NSFW.
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