The problem is the title of Queen (or King) of England has not existed since 1707, and the last person to hold it died in 1714 (as Queen of the United Kingdom).
It is not shorthand for anything. It’s just plain wrong. The fact a lot of people say it doesn’t make it right. It just shows they don’t know what they are talking about.
It makes no more sense than referring to Joe Biden as the President of Texas.
The more important point is that the monarchy should end after her time as Queen - of whatever - is done.