Are you sure you mean Bolivia? Afro-Bolivians weren't even recognized on the census until 2012 in part because they were considered such a small part of Bolivia's population. They only make up 0.22% (compared to Mexico's 1.16%) of the population. The region that would come to be known as Bolivia itself did not have as large an African population as a result of slavery (unlike other places like lower lying Peru and Brazil) because of the cost of transporting slaves into the mountains, most forced labor in Bolivia was being done by Native Americans. Of those Africans who did get taken into Bolivia, many would have died without children working in the Potosi mint. In case you're wondering many Afro-Bolivians live in the places their ancestors lived on in haciendas or escaped to, the Yungas, where many of them adopted local Aymara Native American traditions. It was only in the 1990s that there was a movement to embrace the Afro part of Afro-Bolivians exemplified by the political use of the Saya (a form of African dance created by Afro-Bolivians) which resulted in Afro-Bolivians being placed on the census.
Another reason for much of the erasure of African ancestry in Latin American countries is due to the process of blanqueamiento which meant that more people of African ancestry or mixed African ancestry tried to have children with white (or simply people who weren't African or AS African) people in hopes of making their children fit the cultural ideal (and get better treatment legally). It could also lead to erasure of African ancestry in family histories meaning that many people in Mexico who do have African ancestry don't know it.
I'm not an expert in post-contact admixture throughout the Americas, but at least in Mexico recent research shows a very complex story of gene flow after contact, not just for African but Asian populations as well.
Genetic analyses of modern populations show tremendous diversity throughout Mexico. A study of 500 genomes showed high rates of Asian admixture in Northern Mexico, and "about one-third of the people sampled in Guerrero, the Pacific coastal state that lies nearly 2000 kilometers south of the U.S. border, also had up to 10% Asian ancestry, significantly more than most Mexicans." The origin of this gene flow stems predominantly from Indonesia and the Philippines, and can be traced to the vital trade lines/slave trade between Manila and the port of Acapulco in Guerrero. We've largely forgotten the importance of the transpacific slave trade, and at the time newly arrived Asians were identified only as chino, further erasing the identity of Asian migrants.
As for African admixture, almost all modern Mexican populations carry ~4% African ancestry on average. As we all know, averages can hide a host of complexity. Diving deeper into modern Mexican genetic samples shows a hidden structure and populations with much higher percentages of African alleles. Per the article cited above "in Afro-descendent communities in Guerrero and Oaxaca, many of which remain isolated, people had about 26% African ancestry, most of it from West Africa". A quarter African ancestry is substantial, and is a testament to the role of African populations, both free and enslaved, that contributed to the diversity of colonial Mexico.
Now, if we dive even deeper and examine the bioarchaeological data, the story becomes even more complex. When we examine the skeletal remains from colonial Mexico an interesting pattern emerges. Based on dental and skeletal traits "20% to 40% of the people buried in cemeteries in Mexico City between the 16th and 18th centuries had some African ancestry". This level of contribution to the overall population structure of colonial Mexico City rivals the percentage of Europeans admixture at the time.
This genetic and bioarchaeogical data can help us uncover the emerging population structure following contact. There are still many questions to be asked, and answered, but the story, in its complexity, will be fascinating.