That is from Europe though:
As a factory "accessory" it seems to be available in Europe, in this case from SquadraSportiva in Germany. They state it is a "Genuine Alfa Romeo spare part" P/N 22319, the same as in post #7 above. It is finished in "dark miron" (black metallic with a fraction of brown, finished with clear varnish).
Diffusor / Skid Plate "Veloce" für Stelvio
I plan to order one as soon as I get the shipping quote back if it's not too unreasonable. I also asked them to confirm the model years it is supposed to fit.
They do clearly state "Not suitable for models with hands free tailgate and / or tow bar" so be aware of that.
I'll post their reply for everyone when I get it.
Finally, when I have time, I'll try to submit this part as a suggestion to MoparPartsOnline to include in their accessory line.🤞