Hi buy the eBay version, the part number you gave is for the whole arm which apparently fits the A3,Q3,A4,A6 for that year its good old globalisation, one part fits all and depending on what model you have the price is higher between A3-A6 the A6 part will cost more, I bought my Audi in 2019 and its been a constant battle with the parts but as soon as you rip the only way is Audi theory to shreds its like Ray bans on a sunny day you can see it for what it is, it took me a while to work it out that they the same as all manufacturers buy their parts off the peg from people like Lemforder,Febi,ATE and have their name stuck on the unit but if you look carefully at the unit it normally has the real manufacturers part number and hey presto using that number its a hell of a lot cheaper, Audi are a mixture of Jabba the Hut with the greed and and Gary Glitter with molesting your wallet, my rear wiper motors of which I have had three are made by Valeo they all do the same thing and allow water to run back down the spindle and past the rubber seal and rot the control box out rendering it useless, Audi wanted £300 for the motor and £30 for the grommet seal, end result Ebay £125 the motor and £12 for the grommet, a good place to look for part numbers is LLL car parts they have all the diagrams for your model and when you have the number go fishing on eBay or contact Parts in motion they have just about everything in O.E.grade parts, so it wont be as expensive as you think. I bet your motor is the same as mine.
Steve.