Native American populations were vastly phenotypically, culturally, and genetically variant, but they all arrived from Asia.
The assertion that Olmecs were from Africa has been (throughly) both materially and genetically repudiated by respected scholars.
As of right now, there is no convincing scientific or historical evidence that any indigenous group had a direct cultural or genetic link to Africa.
The academic world of history and anthropology has been very racist in the past in an academic climate that actively promoted white supremacy and neglected peer review. This is generally no longer the case (although there are exceptions). If solid evidence existed for an African link to pre-contact America, a million scholars would jump on it. A book on that shyt would make your career.
The fact is that the supposed "evidence" has been examined and dismissed as complete farce. Most of it is INTENTIONAL misinterpretation and the result of confirmation bias. 100% or nearly 100% of respected African-American scholars agree with this.
I'm completely for the reclamation of black history, a process that continues into the present day, and wouldn't have been necessary if it weren't for years of racism. Black history has been both hidden and neglected. But reclaiming the past CAN be done both within the realm of FACT, and WITHOUT robbing other oppressed groups of their cultural heritage.