How to support farmers that have contracts with American businesses like McDonald's?

McDonald's is very American but they do source a lot of they're ingredients from Canadian farmers and processors like McCain.

If people boycott McDonald's they will cut contracts with farmers like they did in the beginning of the pandemic.

Will this just be the cost of doing business with Americans? Will Canadian farmers and processors prioritize Canadian businesses after this?

The only suggestion I can think of is to buy from McCain directly. This would also be cheaper and healthier.