> I'd wager that Apple has been using AMD for something as mundane as offering better pricing, rather than disagreement 12 years ago. (Again: despite all the lawsuits, Apple is still a major Samsung customer.)

This used to be true, as Apple swapped between AMD and Nvidia chips several times in 2000-2015. Then Nvidia and Apple fell out, and Apple has not used Nvidia chips in new designs in 5 years - a timeframe in which Nvidia coincidentally achieved its largest technical advantages over AMD. Apple goes as far as to actively prevent Nvidia's own macOS eGPU driver from working on modern macOS. A simple pricing dispute does not appear to be a good explanation here.