How did the federal government attempt to aid the newly freed 4 million blacks? Was it a success?

In the aftermath of the American Civil War, the United States government undertook what was an ambitious—albeit, not always effective — program of support and assistance. This was primarily accomplished through the Freedman's Bureau.
The bureau's programs included the provision of food, medical care, housing, legal aid and education to newly emancipated African-Americans from the southern states. The bureau also made efforts to settle ex-slaves on land that been either seized or abandoned during the course of the war. One such program was known as "40 acres and a mule" which granted 40-acre plots of land, and in some cases a mule, to emancipated slaves.
Led by Gen. Oliver Otis Howard, the efficiency of the bureau's efforts were largely curtailed both by a lack of funding and by resentment and hostility in the defeated southern states towards emancipated blacks.
Nevertheless, some of the Freedman's Bureaus efforts remain visible today, in the form of several Historically Black Colleges and Universities (HBCUs), such as Howard University and Hampton University, both of which were established with bureau support.
https://www.archives.gov/publications/prologue/2010/summer/slave-pension.html

https://www.loc.gov/exhibits/african-american-odyssey/reconstruction.html