Don't call POC a uncle tom or anything similar if your not black, ultra cringe. I think the only answer is to publicize the amount of racism and hate crimes in these groups, even my conservative af black grandfather can't convince himself to support the modern republican party. (Even though not much has changed really over time, I think the increased media attention on murders by white supremacists can actually make some POC more open to farther left politics.)

Unfortunately though, if there is a niche for black conservatives (Which there is, having a few black proud boys greatly strengthens the legitimacy of their political influence ) there will always be those who are willing to fill that niche, whether its a form of self preservation by becoming one of them or they truly believe in fascist principles, your energy is far better off spent converting people who actually want the world to get better.