I'm sorry to hear about your AT4. You sound level headed. I don't know if I'd have kept my cool as well.
These kinds of reports bother me, but I am going to have faith. My grandparents, parents and I bought almost exclusively GM for literally over 100 years. (See grandma in one of her Chevys) In the last 30 years, I've had two bathtub Caprices (the best), a Z28 convertible, a Deville and a 2016 Impala. All hassle free, well built, big solid reliable American cars. All our Caddys, Buicks, Pontiacs and Chevys have been great, no exceptions. Toyota reliability without being tinny imports.
I traded in my low milage bulletproof Impala V6 on my diesel Hoe four days ago. The Impala ran like a top for 70k miles. I hesitated to give it up.
Then I read about these problems with the Hoes, throwing lifters, leaking sunroofs. This should not be happening.