EU has two main legal instruments, regulations and directives. One applies directly, the other needs to be transposed into national law which indeed often ends

EU has two main legal instruments, regulations and directives. One applies directly, the other needs to be transposed into national law which indeed often ends with gold plating, but the tool is there to give uniform legislation- if all countries agree. In addition there are plenty of technical standards which are agreed in expert committees, and these too apply directly. I'd expect Canada would join at least those technical processes and the two sides align technical standards over time.