Entirely untrue. The monarch has a weekly meeting with the Prime Minister. There have been many cases of the Queen getting carveouts, influencing laws, and vetting bills. There is no law forbidding the monarch from not granting Royal Assent. This notion that the British monarch has no power is an absolute farce.
There’s also the whole concept of King’s Consent, wherein the King gets to vet every single bill for affect the crown's own prerogatives or interests, and negotiate secretly with the government to change the contents of that bill. The Guardian articles detail this process as well. If you seriously believe the King has no power in practice I have a bridge to sell you.
https://en.m.wikipedia.org/wiki/King%27s_Consent
https://theguardian.com/uk-news/2021/feb/07/revealed-queen-l...
https://theguardian.com/uk-news/2021/feb/08/queen-lobbied-fo...
https://theguardian.com/uk-news/2021/jul/28/queen-secretly-l...
https://theguardian.com/uk-news/2021/jul/28/revealed-queen-v...