I have a flight with British Airways from New Delhi to Toronto via London, just called them. I told them I have COPR, not PR, they said they would allow me to board the flight, but I should ask Canadian Embassy if they would allow me to enter
Tried calling the Canadian embassy in Abu Dhabi (UAE) and couldn't get through. They were very clear that if I have any question pertaining to immigration or Covid-19, then I would need to contact them by email /web form only...