Our greatest monarchs have been women, but they didn't get there other than being second best option.
Not really, Boudi. There was no one for them to be second best to - hence they became the monarch.
You omit Mary I, or bloody Mary, ...
don't forget Lady Jane Grey who was actually Queen for 90 days, was it, but never crowned?
Weren't William and Mary (of Orange) technically asked as a 'couple' as opposed to a King and his consort?
I wasn't giving an exhaustive list, and the two I gave are considered amongst our very greatest monarchs, above most kings, Anne likewise had the Marlborough victories to tuck in her frock, but she's not considered one of our greats. Mary was a regnant queen indeed. Jane was queen for 9 days before her deposition.