Did she have any choice?
I think the British constitution says the monarch must approve all laws passed by Parliament...Otherwise they get Ye Olde Charles The First treatment and lose their heads.
Anyhow, Charlie “The Red Prince” would have approved before the old Queen’s body was cold.
Not quite all - but most. And she has no power to intervene in this case.
The Monarch could refuse assent to a law only if it was unconstitutional. The last time a British Monarch did this was 1708.
George IV considered blocking a Bill in the 1820s that relaxed restrictions on Catholics in Britain, because he was concerned it violated his Oaths concerning the Supremacy of the Church of England, but it was made clear to him by his Ministers that Parliament now reserved such matters to themselves and they were not Constitutional.
The last time a Monarch even considered refusing Royal Assent was in 1914 when George V considered doing so over the Government of Ireland Bill (note - a purely Constitutional Bill, concerning, directly, the government of one of constituent nations of the United Kingdom at the time). Because this was a Bill that affected the Constitution, he could have done so. But he determined that a King should only do so if there was "convincing evidence that it would avert a national disaster".
The Queen does still have some real powers. Including a right to refuse Royal Assent over constitutional matters. But this is not such a case.