I've read a few of the usual sorts saying that Ncuti Gatwa can't be the Doctor because he's not British.
He was born in Rwanda, but moved to Scotland aged two when his family fled the Rwandan genocide. His nationality is British.
Richard E. Grant, that most English of actors, was born in Swaziland (now called Eswatini). It was a British Protectorate at the time, but became independent when Grant was 11. He didn't move to Britain until he was 25. He has dual British and Swazi nationality.
In 2003, Grant was cast as the Doctor in an animated series. It didn't last and was overtaken by the live action series starring Christopher Eccleston. Some fans dismissed Grant's casting because they didn't like him, or dismissed it because it was only animated.
No one ever said he didn't count because he "wasn't British."
I wonder what the difference is now.