Canada is more internally stable, but is less externally stable, given that invasion and occupation is on the table.

Canada needs to pursue further armament (Carney is pursuing a doubling of its defense budget) and training in asymmetrical warfare.

What makes you say "certainly," especially in the hypothetical scenario where the US is unstable? Canada has a relatively much shorter history as an independent nation. Canada heavily benefits from its southern neighbor, and has a host of domestic economic issues (low wages, high housing prices; whatever the farmers are on about) that could cause instability as well. I think Canada is reasonably stable, I just quibble with "certainly" and "more" politically stable as compared with the US.

All historically-stable Western nations seem to be subject to the same influences that brought us Trump, though.

They (we) are all under attack.