When the Queen died, she was actually a Presbyterian. That’s because she was in residence at Balmoral, and all British monarchs change their religious identity when they arrive in Scotland. They board the Royal Train at King’s Cross as Supreme Governor of the Church of England, responsible for appointing bishops whom it teaches are successors of the Apostles. By the time they arrive at Waverley they belong to a Church which has no bishops and whose only Supreme Governor is Jesus. King Charles, who succeeded to the throne in Scotland, did so as an ‘ordinary member’ of the Kirk – which, as the Royal Family’s website explains, is the only religious status that the sovereign enjoys north of the border.
https://www.spectator.co.uk/article/why-queen-elizabeth-was-a-presbyterian-when-she-died
God save them both.