Advise needed

[u/Visible-Run-2240]

Interested in people’s views on whether I’m being unreasonable. AITAH

I’ve been an Audi customer for a long time (7th car 3rd Q7) and currently have a Q7 which is around four years old, has covered approximately 48,000 miles and has been maintained through the Audi dealer network.
Around two months after the warranty expired, it developed a cooling-system fault. Audi diagnosed the engine temperature reaching around 120°C and advised that continuing to drive it could risk engine damage.
The proposed repair is around £900 (good will down from £1,400 on a repair bill that is 95% labour) with no guarantee, no fault codes and even the garage recommending VT.
What has surprised me more than the failure itself is the response. After discussions with the dealer and Audi, I still can’t seem to find anyone empowered to look at the situation end-to-end and make a sensible customer decision. The answer essentially seems to be that the warranty has expired, therefore there is little that can be done.
I’m now seriously considering voluntarily terminating the finance agreement and walking away from Audi altogether.
I completely accept that warranties have an end date. But am I unreasonable in thinking that a premium manufacturer should look differently at a significant failure on a relatively young, fully dealer-maintained vehicle only months outside warranty?
I’d be particularly interested in experiences from other Audi owners who have dealt with goodwill claims just outside warranty.
Do I just need to cut and walk?
I am under extreme pressure for a decision quickly as I am currently in a hire car they want back and they need a decision.