I am from Canada (near Toronto, ON) and when I did my grad studies (MSc and PhD), my department averaged 70-100 grad students at a time (not including the 1-year non-thesis MSc program) with maybe 20-30 postdocs. I would say that only about 10-20% of the department were Canadian citizens with the remainder from various parts of the world -- Middle Eastern, India, China, South America, etc. Many of them would apply for residency and later citizenship, and this I think is good for the country since it keeps highly-skilled scientists in our workforce (There is often a complaint about a "Brain-Drain" as many Canadian scientists leave to work in the USA due to generally higher pay).
Canada is one of the most ethnically-diverse countries in the world as the immigration policy has been very liberal since Canada has a low population spread out over a large land area, so increasing population is seen as helping the economy and infrastructure. Canadians, overall, are very accepting of this and have a reputation for being very tolerant of other's cultural differences. There may be a few professor's who would rather employ Canadian citizens, but I would say it is definitely more the exception.
With the new Trudeau Liberal government coming in, and stating they recognize the importance of funding university education especially the sciences, I would think there will be more future funding for professors to find grad students or postdocs for projects (in contrast to the former Conservative government which cut a lot of funding to universities). From this, I would say you have a good chance of finding a PI that will have funding for you. As you mention in previous threads you have patents from your prior research, then I think you will be in a great position to convince a professor of your value as an incoming postdoc. More important still would be to show your passion for that professor's research area through your knowledge and ideas for future research.
One thing I know for certain is that professors do not like being sent generic "copy & paste" emails sent out to them with grammar and spelling mistakes with no real thought put into their request for a position. This shows no respect for the importance you place on your decision to want to work for that professor. Therefore, carefully think about what you want to say, and proofread your letter several times. If your English is not fluent, then have someone fluent in English proofread it since it should be that important to you. You don't just want to include what you have accomplished, but you want to show you have intimate knowledge of their work by reading their papers and showing you also share a great interest in this topic.
All the best with your search! Do not get discouraged by rejections as it is a numbers game. I am quite certain if you reach out to enough professors in your area of interest, you will eventually find one with funding for you.