The OP asked for examples of discrimination against Whites in black majority countries. South Africa is currently an example. It’s been a very difficult and dangerous situation for decades. They were on the verge of civil war for a long time.
I’m not making any comment about who is right or wrong. Or the long history of White rule in that country. I know it’s incredibly complex and I wouldn’t even consider taking a position. It would require months of reading to even begin to understand the history and politics of SA.
I do know the power base shifted with the election of Nelson Mandela in 1994. The ANC has won elections since 1994 and is firmly in charge.
Land Reform is taking place. It’s a part of the ANC’s rural development program. A law was passed in 2014. It was challenged in court and new laws are being drafted.
A detailed analysis of SA Land restitution policy is beyond the scope of the OP’s question. I’m only providing an example of discrimination against whites. Being required to give up or sell land inherited from your great-great-great grandfather would be a form of discrimination.