There is nothing in “the canon” about skin color.
Agreed. As long as we are being historically accurate. In 1950, James Bond was white. Today? He may be Indian or Black due to the changing demographics of Great Britain.
Then it would allow me to engage in suspension of disbelief as I'm watching the Bond movie.
I guess you haven’t watched it.
If you need a black or blue or green Gallifreyan space-time traveling hero show some creativity and create one. Introduce with an episode using a previous Dr Who. Make up a plausible for the canon reason for his existence. (Since I understand Gallifreyans are supposed to be dead!) Maybe Dr Who can say ‘Well I was wrong about that here’s Dr What!’. Above all show writers, etc show some creativity don’t just be copycats doing cultural appropriation.