There’s a reason Indian tribes are still called Indian tribes in the US and it’s because they’re fine with it. You just treat it as short for indigenous and you’re good.
Well, that's a big lie. I grew up on a reservation, an Indian Service Area, and still work on a reservation. Native American, Indian, American Indian are all used.
indigenous is the not a term originating with any tribe.
They are not such enormous fans of the term that you should be going around telling people to use it over other ones. And white people (who think “Indian” is a slur) do go around telling people this.