Thanks for joining us and for posting your topic. The Amstaff and Cane Corso are far apart in size and termperment but let me give this a try and ask a few more questions.

Do you want a dog with a double coat to be out in the Canadian winter?

Do you have a fenced in property?

Off the cuff, I would say a good German Shepherd or a Belgian Malinois may fit the bill.  However, if you want something that "look like" the Amstaff or Cane Corso but have the qualities you describe you could consider the Boerboel or even the Cane Corso.

In the furry category you can consider the Alaskan Malamute, Central Asian Ovcharka, the Danish Broholmer. For something smaller that will be a good watch dog you could consider one of the Laikas.

Please provide any other information about your situation that would help us to provide a better answer for you.

Best regards