Change the path used by a route dynamically
I don't believe that there is any need for custom route manipulation in your case, and besides, while I am not entirely sure, I don't think that something like what you describe, would actually work, since then you might have issues with the view's contextual filtering.
I believe the TVI Module is the answer to your problem. It can be used to specify the view/views that will be used in the vocabularies of your choice.