Find a pilot with their own plane to fly you down to the states, or hell even all the way to africa. Won't be hard, pilots are almost always looking to get some flying time in.

This is assuming that US customs isn't enforcing vax requirements, just Canada. Now you're here legally and free to go about your day. I have no idea if that would require a visa or any of the other shit, but that way you will get your passport stamped from the us and nothing would look weird when you get to customs in Africa. All of that may not be necessary at all I have absolutely no clue, just trying to cover your bases, I'm sure it can be done legally, but it may add some expense well worth over a vax.