'Isn't the desire to end desire a paradox?'
Suppose you grab a log and you caught a splinter. This splinter is a sharp foreign object and it would be wise to remove it (it could lead to an infection). To remove it we could make use of a (disinfected) needle. A needle is another sharp foreign object. So, we use a sharp foreign object to remove a sharp foreign object. Do you see any paradox in there?
We don't just stick a needle in there and leave it there too, that would not be skilful. When the splinter has come out that needle is easily cleaned and put away. And with it the deside to remove the splinter is away too.
The desire on the path can be compared to the desire to make use of the needle to remove the splinter. Letting go of all desire is in that sense more about implying what will be done instead of something that you need to focus on as need to do. So don't erroneously try to take all the desire and fun for the path away; skilful desire leads to the end of desire and it is something that must be created.