The Canadian government  must have foreseen this because they have you covered! Foreign nationals in Canada whose temporary residency status is expiring soon may be able to extend their stay in Canada.

Temporary residents who cannot leave Canada due to Covid 19 restrictions can apply to extend their residency status. The application needs to provide the Immigration, Refugees and Citizenship Canada (IRCC) an explanation as to why they need to stay in Canada as well as other requirements as stated by the government.