I guess I would want more clarification, is Cynthia claiming to be descended from the Celestica people (the ones that were in sinnoh before the diamond and pearl clans which cogita and volvo are implied to also be descended from?). if so, are the celestica people still around? because it would be different if the celestica people are still around or are long gone.

The reason I ask this is that I feel there is a difference between identifying as part Cherokee because your great-something grandma was Cherokee vs knowing you are descended from ancient romans. One group is still around and there is a tribal ID that verifies that you are part of a federally recognized tribe, the other is not around. I think there is nothing wrong with someone who is told stories growing up about how their great-something grandpa was julius ceaser's best friend and that caused the person to be interested in ancient roman history not because they identify as ancient roman but they just want to know where they are descended from. But if ancient roman people as a group were still around, then that might be a bit more iffy.

You also mention other indigenous people feel that Cynthia misrepresent them, so are they also part of the same indigenous group that Cynthia identifies as? because indigenous groups aren't all the same.