Are you desperate to change?
I paid £20k for my 2012 Allroad 2.0 TDI 177PS back in 2015 with xenon headlightights, Alcantara and leather, satellite navigation, LED tail lights, cruise control and a panoramic sunroof with 30k miles. It was also tow bar equipped which was on my 'must have' checklist.
What's different about 2 year old model? If it's diesel, then you're into Euro 6 territory and potential AdBlue pump failures. I doubt VAG have done anything about the panoramic sunroof leaks that have plagued owners. It's a design flaw and already noted on Skoda and Volkswagen models. Headlights have moved on granted with matrix technology, but the xenon headlights were a revelation after coming from previous Audi's with projector headlights. Lane assist and adaptive cruise I can live without, but you can't stop progress.
I even updated my satellite navigation last year as trips to Glasgow saw me literally driving across fields as it was so out of date. I refuse to pay Audi £250 when I can do it myself.
A critical bit for me, the new model is still on conventional coil springs. Audi know this is a compromise, given the superior air suspension on the A6 Allroad. The A4 Allroad isn't bad, it's a very smooth ride, but it's a soft roader no more.
Yes the interior has been completely revamped, but let's face it the older B8 interior wasn't exactly poverty stricken. I have no complaints over interior build and refinement.
Back to your point, I'm sure covid related issues have effected the supply chain, but no way would I pay £30-35k for basically the same car technology wise Hey just my take on it.
If it were me, just sit until Audi pull something from the bag, they're not even offering hybrid technology. Granted you're going to pay too dollar for this, but my point is your 2015 model is probably sweet as a nut.
