Nah, what he promised him is exactly what we see: $500B in rare earths, every year. Trump’s always been a terrible dealer, and this is no exception: he doesn’t do back-and-forth, he just tosses his entire hand on the table and says “here’s what I want”, then bullies you into accepting. If you don’t, he’ll either harass you, or back out saying YOU sabotaged the deal because you didn’t give him what he wanted immediately.

Pretty much this. Even with modern equipment, it would be a huge feat of engineering to fix the locks in a short enough timeframe to not have a huge effect on the world economy. Without the Panama Canal, cargo ships are gonna be burning WEEKS navigating around the Cape or coming around through the Arctic.