"Surely, when/if Prince William becomes King, her title will be Queen? I believe that technically she would be Queen consort, but her title would still be Queen Catherine."
Technically she would be a Queen Consort, that is to say that she would not inherit the throne on her husbands death. However technically her Husband is known as a King Regent, both are usually just shortened to King and Queen.
Camilla is, allegedly, going to be a Princess Consort so as not to take on the title of "Queen".
Philip is not a King Consort, he's not even a Prince Consort, he's the Duke of Edinburgh. He's never been formally named as anything other than that.
We don't, as a rule, seem to ever have an explicit King Consort. Queen Victoria wanted to name Albert that but Parliament refused it, so he got Prince Consort instead.