Not completely. Even given China's enormous manufacturing capacity, there are still gaps in it. China very definitely prioritizes the manufacturing, even after the opening up of the economy to private entrepreneurs. For instance, it has delegated cities of well over a million people each to a dedicated task - one to robotics and the other to quantum computing. Everything in the city - infrastructure, education, facilities, governance - is directed towards these focus centers of excellence.
If it is not high on the government priority list, it is fair game to outside countries to fill the gap. America just does not want to manufacture what China wants. If Canada decides to do so,the opportunities are there.
It depends on exactly what you mean by 'bricked'. Take over the operation of the car, or just cause it to stop functioning? Teslas are easy to disable remotely. Just botch up the navigation system. But to cause them to deliberately crash? Takeover the complete control of the car?