It's purely ceremonial, my guy. Ill give you an American equivalent. Its like the role that the vice president of the United States plays on the 6th of January during the certification of the November election.
Do you honestly believe that the American people can vote for a president and then the Vice President has the power to say "No im not certifying the election results" and then we hold another election?
Even Pence wasn't that stupid when Trump wanted him to do it. Yes he certifies the results but it's purely ceremonial. He has no authority to do anything different.
Same for the queen. Yes she has the ceremonial power to dissolve parliament. Meaning that when the majority party or whoever has the REAL power decides that parliament should be dissolved, then yes she ceremonially does it.
But if you think the Queen could wake up one day and say "I'm unhappy with the way things are going, it's time for a new parliament" and then go in and dissolve it, that's the craziest thing I've heard in my life and it shows you have no knowledge or understanding of UK politics at all.
If you think the Queen could go in and say "hey I've decided that we're going to join Ukraine and declare war on Russia", you a fool