Yes, all fair points and questions. The best I can do is see if their latest offer is sufficient and go from there.If you're legitimately worried about the tune causing a catastrophic engine issue, just know that any subsequent updates from APR are probably aimed more on drivability rather than correcting some parameter that affects reliability. I noticed that you're running the HT file so you could move to the LT file which would obviously be easier on the car over a long period of time, but that's a small ask from a dealer who has been completely dishonest with you.
If it's not going to be a warranty backed by VW, what's left? The possibility of some sort of written agreement between you and the dealer that basically says because the vehicle was sold under a false pretense, for a period of time/ mileage we will cover any issues? Idk that seems pretty flimsy to me and that's why I'd ask a lawyer what your options are.
What if the GM of the dealer is caught snorting cocaine off of the ass cheek of his mistress in the service bay and loses the business? What if you're offered a job in a new city on the other side of the country, but you have this agreement with this dealer? All things to consider.
Edit: by the way, the low torque tune is exactly the tune I want to switch to.