.The Americans were not primarily concerned with conquering Canada.
They most certainly were. The Yanks wanted to acquire the Northwest Territory, which included a vast swathe of Canada. Indians in that area were opposed to this Yank expanionism, and allied themselves with the British, who were treated far better under British rule than they would be under brutal Yank rule.
The British were interested in preventing the rise of a new great power in the western hemisphere.
No, they weren't. The American colonies were not that important. They were minor colonies to the British, compared to colonies like India. There was no indication at the time that the US would become a great power.
Britain feared invasion, and used its trade embargo to weaken the French. However, Britain's trade embargo was unlawful when imposed on a neutral power such as the United States. Britain did commit acts of war against America in enforcing the embargo. Britain did deny America the freedom of the high seas.
The
Berlin Decree of 1806 forbade French, allied or neutral ships trading with Britain. By this means Napoleon hoped to destroy British trade, disrupt its growing industrial expansion - Britain was on its way to achieving global economic dominance - and diminish its credit.
Great Britain responded with the
Orders in Council of 1807 issued 11 November 1807. These forbade French trade with the United Kingdom, its allies, or neutrals (such as the USA), and instructed the Royal Navy to blockade French and allied ports. This order required all shipment to stop in English ports to be checked for military supplies that could have aided France. Ships that did not stop to be checked at English ports were liable to British seizure.
So you can actually blame the French for the British embargo on the USA, because if they had never placed such an embargo on the British in the first place then the British would never have replied in kind with an embargo on the French, which affected the USA.
Of course, most Yanks would never have been taught all this in history lessons.
Also, to say the embargo was "unlawful in international law" is untrue. The Ynaks, of course, tried to CLAIM it was unlawful under international law, but whether it actually was is debateable.