I looked at options for several months, imported rubbish items that allegedly fitted (mine was a 2023 vehicle), but didn't and then noted that a friend's FR
Ateca's rear bumper looked tantalisingly similar, took the plunge and ordered a set. With time and patience they could have been made to fit better but I was awaiting a knee op at the time and couldn't spent lots of time kneeling on the
garage floor making them fit perfectly. Your original post will attracted lots of views because the Cupra
Ateca throws lots of road crud up onto the rear of the vehicle and as you have noted there is no official part for the job - the part number needed is in my post - not cheap though.
If you go down the mudflap road then the mud deflectors for the rear wheel arches that stop crud been thrown up onto the rear faces of back doors is another worthwhile (and inexpensive) mod: