Watermarking Text in Channel Per User

I have a paid discord channel where I share content with subscribers.  This is on the order of hundreds of users.  One user is copying my articles and is reusing them without my authorization.  I would obviously like to find out who it is.  The way I have thought about doing this is to have the discord channel embed invisible characters into the text (e.g. after each word) that is specific to the user viewing the channel.  This would only apply to plain text (not images, attached files, or quoted text).

Example: 

I post to Channel A the following text: “A quick brown fox jumped over the lazy dog”.

If user A is viewing the text in Channel A, they would see a rendition of: “A<c1>quick<c2>brown<c3>fox<c4>jumped<c5>over<c6>the lazy dog” - where c1-c6 are invisible characters; 

while user B would get some other variation: 

“A<c2>quick<c1>brown<c3>fox<c4>jumped<c5>over<c6>the lazy dog”

where c1-c6 are some invisible unicode characters.

The ordering of these invisible characters would be unique to each user that is assigned to them when they join my server.  

1) Only I as the administrator userwould be able to see this unique signature for each user.  

2) I as the administrator can denote a channel to be watermarked without users' knowledge.  When a channel is watermarked, every rendered post contains some invisible character between words.