I'm not arguing pre-1945 was less violent than the Cold War. Pre-1945 was a multipolar world order vs a bipolar order during the Cold War. Post-1991 has been a unipolar world order with the US as the sole superpower and global hegemon.
It's an odd thing to argue that Canada and the world will be safer with a strong China. It's already creating a security dilemma. The same thing that triggered an arms race, the Cuban missile crisis, wars like Vietnam/Korea, and countless regime changes, proxy wars, and civil wars in the 3rd world. Much more dangerous than a few terrorist groups blowing up some buildings. Ukraine is a proxy war, and Taiwan would be also.
The fewer totalitarian superpowers the better.
https://en.wikipedia.org/wiki/Security_dilemma