Let's take the racial (genetic and cultural) issues out and look at the science.
More testing. The US has not and is not testing enough to provide the data in enough numbers and rapidly enough. Inadequate testing is not proof that testing doesn't work.
Masks do slow the spread. Again Trump and his followers have opposed and even ridiculed mask use. while public health officials supported their use. So...non-users such as Trump and much of the White House were infected.
North Dakota spiked after their motor cycle weekend, and OK after Trump's rally. We now have rigorous testing that supports that masks protect both the users and others. You are critical of changes in public health recommendations, but the public health recommendations have been far, far more consistent since February (wash hands, wear a mask, socially distance, etc.), and their predictions more accurate than Trump's claims that the virus wasn't serious, would go away in the spring, would go away in the summer, was only the flu, etc. etc.. None of which were true.
Contact tracing. Contact tracing works before the virus has spread into the community to keep it from spending into the community Once a virus is out in the general population, it is too late.. Countries and communities that locked down early and used contact tracing have controlled the virus. The key difference between Korea and the US was not genetics or culture but if the country had leadership and acted quickly to take public health measures. Trump, Pence, Kusher, etc. were clueless and ignored the pandemic play book that was sitting on the White House shelf.
As the Woodward book testifies, Trump knew in February that the virus was deadly and decided not only to conceal the facts but to actively lie about them right until the bitter end....whenever that is.