Race/ethnicity/culture can be done badly or well, just like anywhere else. DA: Inquisition does it badly: it's just a random rainbow coalition occasionally giving some really uncomfortable unintended consequences, like the pro-police-violence black lady Vivienne.
Pillars IMO does it rather well. Cultures cut across fantasy-racial lines (e.g. the elven-human Aedyran culture with its peculiar institutions, or the orlan-human Glanfathans, etc.), and there is a correlation between ethnicity and culture but it's not 100% categorical. Most Vailians are black humans but not all black humans are Vailians and not all Vailians are black or human. Same for Rauatai and aumaua and what have you.
(That shit about race mixing is edgelord bullshit ofc. Races have always mixed. Empires in particular were giant melting-pots, the Romans for example recruited all over the Empire and then moved the legions all the way across the empire so they would lose any local power base and connections they might have and become more dependent on the central power and therefore more loyal. Roman Germania and Britain were full of Syrians, Africans, Iberians, and what have you.)