The convoy people were primarily centered around the ongoing restrictions that Canada had imposed around covid.
Something that isn't always clear to people in the UK is that Canada had some really significant, and also quite stupid, restrictions a lot longer than the UK did.
They also managed to be very authoritarian about making people get vaccinated. Not directly by making a law, but by encouraging workplaces to require it of employees. So, I worked in a library at the time, had I not shown proof of vaccination I'd have had to go on unpaid leave. But it also applied in some bizarre instances. I knew one man who mainly worked along in the woods, but in order to sell his wood chips to the power plant, he had to be vaccinated. And another gas station owner - he used to have ambulances from the hospital next door fill up at his station. He was told he could not keep that contract unless all of his employees were vaccinated, because the rule was all hospital workers, including those employed through contracts, had to be vaccinated.
Masking was also mandated in some provinces way past the time the UK had given it up.
The issue with the truckers was mainly about border crossings. Many of them are crossing the border to the US quite regularly. There were a lot of restrictions placed on border crossings until quite late in the game, including requiring people to be vaccinated, and to register ahead online with the date and time they were going to get to the border crossing. This was well past the point that anyone thought that it would actually be possible to stop covid from acting like other respiratory viruses and spreading, and it was also clear that the vaccination did not preclude spreading the virus. There were also still very significant hold ups at the border.
The idea that they were all Nazis is just untrue. They were regular working class people, who do tend to be somewhat socially conservative, but that's hardly the same thing.