An alternate South Africa and the Orange Republic

After the British attempted to impose a system of confederation on the South African colonies, the Dutch settlers of South Africa (also known as the 'Boers') protested and revolted in 1880. The Boers stood their ground against the British very firmly as the British found themselves outmaneuvered and outperformed by the highly mobile and skilled Boer marksmen. With a British commander-in-chief is killed in action and British garrisons under siege across the entire Transvaal, the British signed a truce and peace treaty to end the war. Transvaal remained a self-governing state under theoretical British oversight. Many new Dutch settlers migrated to the region in the years after.

Transvaal received payments from the Netherlands in order to develop the region. People of British heritage were second class citizens in Transvaal under president Paul Kruger, who wanted the region to stay under ethnic Boer control. The discovery of gold in Transvaal and the Orange Free State presented an additional interest in the regions for the British. In 1899 a British colonial secretary demanded full voting rights and representation for British citizens of Transvaal. President Kruger responded with an ultimatum for Great Britain to immediately withdraw its troops from the borders of the Boer states. When the ultimatum was rejected, the Orange Free State and Transvaal declared war on Britain. The Boers were aided by the Netherlands and the Zulus, who were recently annexed by the British in the Anglo-Zulu war. The Boers won a series of pre-emptive strikes against the British who were overconfident and under-prepared. After these losses, Britain send new troops and pushed further into the Boer states. The Netherlands were hesitant to let the colonies go because of the large amounts of gold that could be found there and for that reason, greatly increased the troops send to South Africa. The war proceded partly under guerrilla tactics against the British forces. The British responded with a scorched earth policy of destroying Boer farms and moving civilians into concentration camps. The war dragged on until September 1903, when the British finally proposed peace. In the Treaty of Bloemfontein, drafted on 28 december 1903, it was declared that Transvaal and the Orange Free State remained independent states and that Zululand was to cede to Transvaal. Also, Britain was to pay reparations caused by the war and imprisonment of civilians in concentration camps.

The Cape Colonies become independent in 1905, forming the South African Union. In 1921 Transvaal, the Orange Free State and Basutoland merged into the Orange Republic, a constituent country of the Kingdom of the Netherlands, similar to Aruba or Curaçao. This decision was made by the Boers because of the considerable Dutch influence in the Boer wars. Under Boer control, segregation and racial inequality stay very prevalent in the Republic. This fades away in South Africa, as the region is majority Afrikaans. The British don't enforce racial discrimination unto the country and after their independence, South Africa falls under Afrikaner control. In the Orange Republic however, a racial war erupts in the 70's, causing many black and white casualties. The bastion of white supremacy is finally taken down in 1982, when the nation became fully independent. A federal republic was formed, called the Federal Republic of South-East Africa, still frequently called the Orange Republic. The republic consist of eight federal states: Free State, Lesotho, Kwazulu-Natal, Mpumalanga, Swaziland, Gauteng, Limpopo and North-West.

To see a demographical map of this alternate history, please see the other map in this series:
'Ethnicities of South Africa and the Orange Republic'

TL;DR
The Boer (Dutch settlers) states win the Second Boer War against the British with Dutch aid and form the Orange Republic. Apartheid is prevented in South Africa, but a race war emerges in the Boer states.