The election of Black faces to high places does not change the conditions of life for Black Americans in general. One individual Black man achieving the presidency does not magically heal an entire society ... it produced the racist Trump phenomenon. As Ibram X Kendi explained in "Stamped from the Beginning," racial progress happens alongside racist progress. The Republican Party has become a White Nationalist party openly contemptuous of free and fair elections and liberal multi-party democracy.
Sounds like you've consumed too much John C Calhoun and Mein Kampf.
Equating BLM, a social justice movement, with the KKK, a white supremacist terror organization, is absurd.
The United States has been an intensely racist society over its history. Most White Americans today, that is Republicans, remain deeply racist ... to the point that they love a racist fascist billionaire authoritarian and want to violently overturn democratic elections to permanently install their favorite Confederate flag waving fascist as dictator for life.