At what point did the British Royal family become figureheads of state?

I was watching this documentary series on Netflix called Monarchy UK. It was really gripping, but ended shortly after Cromwell’s death. They did mention re-instating the monarchy and putting Charles II on the throne, but there was no mention of what powers that king had.

I know that Queen Elizabeth II doesn’t have any real rights or responsibilities as a queen except for ceremonial purposes and I was just wondering when did this change happen? Did Queen Victoria have any power on the throne, for instance? I am guessing the decline of power began after Cromwell (Magna Carta aside, because Kings still had a pretty strong hand even with it) but I wasn’t sure how fast it took for things to change to what they are today.

I assume the change was gradual, but I was just curious as to about when did the position of King or Queen become almost purely ceremonial and symbolic?

Feel free to link to interesting sites! I was having trouble muddling through wikipedia because it just states the facts and doesn’t get into exactly how much power did each Monarch possess.