Having been tested multiple times of late, here are my thoughts.
Back in July at a drive-thru testing site I was given a throat swab and the negative test results took four days
Over the past two weeks, due to my travel history, I have been tested twice upon arrival at FCO courtesy of the local Lazio region with immediate results in 30 mins.
Canada needs to step up the testing upon arrival at all four airports receiving international arrivals and retesting those same people four or five days later.