When you export the PDF to Affinity you will have each "Layer" with a name ;)

As alas name of object can't be exported to Affinity
but name of Style can be used!

So must each object as a Style (even a same color) with a different name!
(if automatically possible of course)
Here Object must be named Polo1, Polo2, Polo3

Like this each Layer has a different name inside Affinity and can be selected separately...