Britain, known as the "empire that never falls", is the largest colonial empire in human history. Canada, Australia, New Zealand and other countries were once British colonies. However, from the end of 19 to the beginning of the 20th century, Britain's national strength gradually declined.
With the decline of national strength, it is increasingly difficult for Britain to maintain a huge colonial system. So Britain decided to give some colonies greater autonomy, mainly those colonies close to Britain in strategic interests, culture, blood relationship and so on.
But Britain did not make these colonies completely independent, but made them autonomous territories of the British Empire. The Dominion has completely independent internal and trade policies, an independent army and a limited independent foreign policy, while the head of state is still the king of England.
With the passage of time, Canada, Australia and New Zealand became completely independent countries, but due to historical reasons, they still recognized the King of England as the head of state and formed a "dynasty alliance" with Britain as the head of state.
Although the heads of state are all British kings, Canada, Australia, New Zealand and other countries have equal legal status with the British mainland and are sovereign and independent countries. Therefore, although the head of state is the same person, Britain has no right to interfere in the internal affairs of these countries.
After the death of Elizabeth II, her descendants will become their heads of state according to the constitutions of these countries, not according to the principle of inheritance. Therefore, in fact, neither Canadians nor Australians can be called "people of the Queen".