Well, game freak is still a Japanese developer. Mario Cart is a very computationally light concept, as usually are Mario games, idk about odyssey in particular though, but they tend to be small maps with small amount of entities each. Zelda is fair, I’ve heard good things about it.
It’s easy to make a good performing game if its concept and art design are computationally light. Optimization is about turning a computationally hard problem into a light algorithm that doesn’t take much resources.
Hardware signing stuff is not a real solution. It’s security through obscurity.
If someone has access to the hardware, they technically have access to the private key that the hardware uses to sign things.
A determined malicious actor could take that key and sign whatever they want to.