You should not book a place AirBnB or other wise without you telling them why you are booking it, to do so is very irresponsible, some owners are ok with it. Most are not. It took me talking to many owners to get a place to self isolate. Correct, get a place that doesn't have a shared house with another tenant in the basement etc.
Do not take the self isolate rules lightly and do not try to go around the laws that are in place, if you won't do them then don't come to Canada. Why would you want to risk infecting people here.