I just picked up my new 2023 Arteon R line on Wednesday, traded in my 2018 R-line. I asked the exact same question to the dealer, they couldn't confirm the exact changes but from driving the new one compared to my old one (56,000k's) the difference in the drive is astonishing, it really is like chalk and cheese.

The new car feels unbelievably smooth, more quieter, the shifts are far smoother and the engine and throttle feel much more responsive. It now drives like a much more refined car.

I know my response has zero technical element to it but this is all I can say regarding performance from a non tech person, sorry.

Do keep in mind that you will loose things like the;

analogue clock
swipe foot under boot to open
timed close on boot
no adjustable headrest on front seats
only 2 exhaust tips, not 4
bumper has fake exhaust holes, not actually a hole like my old model

I am sure there will be more things I haven't noticed but all in all it's now a beautiful car to drive.