I only had my allroad a litte over a week ago, bit the bullet and purchased a genuine unit from https://www.gendan.co.uk uk supplier Ross-tech and only a hour or so away from me.
I already had a carista dongle I picked up years ago for my other vehicles which I used to check the car before purchasing...
It has error checking functionality and some modification options but not nearly as much as the VAGCOM has, but only around ยฃ35 on Amazon, if your interested in this see https://caristaapp.com/en/supported-cars for what it can do on the A6.
I was after something that could complete towbar coding and know the value of having additional access to the systems after using a IID tool for years with my departed Discovery.