An intervention on the household someone is raised in is not the same as an intervention on race. This is part of what it means when people say racism is a structural problem: people are, systematically, treated differently in many different parts of their lives. The USA is a country where, within living memory, the insurrection act was invoked to allow black children to attend a school which wanted to segregate them.

Leaving aside the question of what IQ actually measures, the authors of the single study you cite interpret the results as inconclusive due to confounding factors. The mainstream position in biology is that race is not a biological concept [1]. It seems that you are trying to argue that there is some immutable difference between races, a position usually described as scientific racism. As you are not aware of evidence-based arguments against scientific racism, there are studies showing a reduction of the "Racial IQ Gap" [2], as well as papers reviewing scientific racism in the literature [3] where it is argued that much contemporary research promoting ideas of immutable racial differences fail to meet evidentiary and ethical standards.

[1] https://pmc.ncbi.nlm.nih.gov/articles/PMC11291859/ [2] http://www.iapsych.com/iqmr/fe/LinkedDocuments/dickens2006a.... [3] https://psycnet.apa.org/doiLanding?doi=10.1037%2Famp0001228