Pretty much all the colonies acquired by the Brits were acquired with better weaponry, pretty much like all wars fought by Americans. If I ask you to name colonies acquired by the Brits who had better or equal weaponry you'll struggle to find any examples, same with wars won by Americans, that's why when you say "That's why Americans and Brits took over the entire globe. Because we are bad at fighting? More like the best!" it's not accurate since it was mostly done with better technology and weaponry not because they were "better at fighting".
@KBE6EKCTAH_CCP was talking about hand to hand combat when he talked about pitting Pashtuns/Sikhs vs Americans/Brits. Counter arguing what he said with "Brits and Americans conquered the world so they're better at fighting" is not a valid argument.
Also the blue eyes and red hair genes present in the UK and America mostly come from Iberia originally since the Celts are descended from a group of tribes which arrived from Iberia around 5000 BC. Then you also have Nordic countries with similar genes and their colonisation of Great Britain and some parts of Europe and reproducing with its local populations also helped with that spread of genes.