You won't need to touch the steering column, but you may need a new clock spring/slip ring/squib and stalks with the right options for your car plus heating contacts.
Here is an example
https://www.ebay.co.uk/itm/374026328939 - You can see the "Y" connector at the top left in the pictures. That one has adaptive cruise and a rear wiper, but does not have lane assist..... so won't work for an A8..... but they are interchangeable across the MLB platform which means it is exactly the same install as my current Q7.
As you already have a wheel, Kufatec will source one and sell it along with the wiring and a coding dongle for €790
https://www.kufatec.com/en/comfort-r...audi-mlb-45370.
Or you can source one from ebay or a dealer and just use the cable
https://www.kufatec.com/en/comfort-r...i-vw-mlb-45367 and code with OBDEleven or VCDS, which is what I have typically done.