I'm no big fan of Trudeau either - my take on Canadian politics right now is that you have an anti-Trudeau cult that hates Trudeau and thinks he can do nothing right and a pro-Trudeau hive that loves Trudeau and thinks he can do nothing wrong with neither group being able to rise above it and look at things objectively.
Having said that, I don't agree with your take on the video. I've been amazed at how successfully the "cult" has been able to take this video over and make it sound like Trudeau came off as weak. I don't see that at all. I see Xi and Trudeau having a very tense conversation, neither of them looking weak, things ending with a perfunctory handshake and both of them walking off. To be clear, I do not see Trudeau as a particularly strong leader in general terms, but I personally don't see the weakness in Trudeau in this video.
As for questions about the military, Canada could raise spending to 2% of GDP and it would mean nothing. Militarily we're a small power and because we have a relatively large and strong economy we get to punch above our weight diplomatically on the world stage. But the reality is that there are three great powers in the world today - the USA, Russia and China - and no matter how much we spent on the military we would be helpless against any of them.