That has more to do with driver compatibility. “Engineered for NVIDIA” does not mean your AMD is going to have a disadvantage unless the game just came out. And when it comes to AAA titles you’ve either got the power or you don’t. If the drivers are up to date for the game in question, how you program a game is not really that big of a concern.

It’s just branding deals most of the time. They are not using some secret property tech.