I’ve heard before that there is a tendency of these tests to over-report European ancestry and under-report or misidentify ethnic minorities. Something to do with the underlying datasets not being inclusive enough because those populations are smaller and don’t purchase these DNA tests at the same rate as Western Europeans.
There also seems to be a weird fetishisation of First Nations ancestry in parts of the US. I’ve also been told I have Cherokee ancestors, but it didn’t show in my dna ancestory either.