More or less - she does have a wide range of powers but in most cases, they should only be exercised “on the advice of her Ministers” which basically means she rubber stamps what the government wants.
But if the system breaks down for any reason, she can step in resolve a crisis.
And it is far better that if she’s a potential crisis developing, she would warn her Prime Minister in private to not let it reach the stage that she might have to intervene.
And she must be ever mindful of the fact that the House of Commons could abolish the Monarchy by a simple vote. Her last act as Queen would be to sign that into law.
That means the ultimate power is also in a sense with the House of Commons. They can abolish the Monarchy. They’ve done so once before. They also took steps once to replace a King with another (James with William and Mary), and as recently as the 1930s it was made clear that if the government will not accept a King, he really has to abdicate and let the next in line take over.
The first DIVORCED monarch to be head of the Church of England since Henry VIII?
Figure the odds.