Erm...yeah, so this is literally exactly wrong.
Constitutional monarchy is
explicitly not absolute power. Like, that's literally part of the definition of "constitutional monarchy."
Any government that limits the power of the royal sovereign by way of a constitution is, definitionally, not a government where the royal sovereign holds absolute power. As Brittanica.com puts it: "
Constitutional monarchy, system of government in which a monarch (
see monarchy) shares power with a constitutionally organized government. The monarch may be the de facto head of state or a purely ceremonial leader. The
constitution allocates the rest of the government’s power to the legislature and judiciary." (Emphasis and links in original.)
The power is shared, and therefore is not absolute. Period. Canada does not have an absolute monarch. It has a constitutional monarch, whose role is largely ceremonial.* Were the Queen to exercise any effort at absolute power, the Canadian government would make her role
truly ceremonial. Just as how, in England, the Queen
theoretically has the ability to deny Royal Assent to any law, an absolute veto that Parliament can't override. It hasn't been used since the 19th century because the monarchs of England have understood that doing so would be political suicide. Royal Assent is effectively a rubber stamp.
*Properly speaking, the role isn't even fulfilled by the Queen. It's fulfilled by the Governor General, who while
theoretically appointed by the Queen, is appointed so "on the advice" of the Canadian PM. Note here that this term, "advice," in constitutional law means something much different from its ordinary usage; this "advice" is
legally binding, meaning the Queen doesn't get to decide "no, I'm going to nominate X person instead." Should she truly object to an appointment, there would likely be a polite closed-door discussion about an alternative appointment, but ultimately, her authority is again a rubber stamp and nothing more.