If you fly home via a U.S. airport and drive across the land border, you will need to present a negative Covid test taken in the U.S. My interpretation is if you're originating in another country like a Caribbean island for example, you would need two tests - one before flying to the U.S. and then another one taken in the U.S. before driving to Canada. Many U.S. hub airports have clinics that offer the rapid ID Now tests (not free, around $200 or so) that provide results in 15 minutes. So while the government has created some obstacles when using the land border method, it's not impossible to overcome and still less draconian than paying for a 3-night hotel prison.