Right-wing groups and media are really pushing the idea that elites are aiming to replace white people with coloured immigrants, but it has been going on for centuries, just in reverse.
Of course, the modern version is a ruse to push for white superiority, in the typical ploy of playing the victim. This is most disingenuous given that white people have been performing their own great replacement of coloured peoples for centuries. Having brought slaves to the US, once they were given so-called freedom, successive governments proceeded to exclude them from many of the benefits that white people received, cementing in place a wealth disparity that continues to the present.
When the US government gave out low-interest loans, secret plans had areas marked in red as too risky to provide support for, which were almost exclusively areas populated by people of colour. This scheme, known as redlining, effectively sabotaged whole generations of coloured people from building up equity in property. And even when supposedly abandoned, the practice has left a legacy of poor credit ratings in those communities, while those who did receive the cheap loans went on to build substantial wealth as their increased equity and better sale values allowed them to pass on their wealth.
Whole successful black communities were burnt down and murdered in the streets. There were the successive drives to clear indigenous peoples off their traditional lands to use it for white people. This happened, and still happens, not only in the US, but Brazil and other countries with substantial non-white minorities. Colonialism is the epitome of a great replacement, with its suppression of local peoples and their customs, and instilling supposedly civilised governments that were often more barbarous than the conquered.
Effectively, this talk of the so-called great replacement of whites is a cover for their other cause célèbre, banning Critical Race Theory (CRT), which looks at exactly the types of discrimination that underlined their own replacement efforts. To counter its use, white right-wing activists, media and politicians are progressively covering up use of those nefarious efforts by attempting to prevent any talk in schools of the negative effects of slavery and suppression of minorities to increase white power. Those efforts include book-banning, and replacing them with revisionist history books.
Essentially, white people trying all these tactics are proving that they are not the superior race, because despite all their efforts, they are too overtaken with their own sense of inferiority to stand together with others as equals. Suppression, violence and sabotage are not hallmarks of superiority, but an admission of incompetence in the management of their own being. A person who knows they are better in some area of life and is comfortable with that does not need to force other people to recognise it. The real strength is in the knowing, not the forcing.