Hub adaptors are available like these:
https://rover.ebay.com/rover/0/0/0?mpre=https://www.ebay.co.uk/ulk/itm/160961292314
Also, you could try wobble bolts.
Buts it’s not straight forward... the sportier Alfas have different rim and tyre sizes front and back. ie. The Alfa wheels are 19” diameter, 8.5J, ET34 (Front) or 10J, ET41 (Rear).
Cupra wheels are 19/8J/ET50. If you used the front wheels, they would stick out 28.5mm further than OEM wheels, then you would need to add 20mm adaptors on top of this. +/- 10 mm is normally ok, but these would be +28.5 to +48.5mm depending upon how they were mounted.