I don't understand your gripe?
Reachmen are a GROUP of RACIAL Bretons. Bretons are the Medieval French.
You're looking for a Tamrielic equivalent of Native Americans. Native Americans aren't a RACE of humans but a GROUP. What you're really looking for is a culture.
Skaal are animistic with a strange monotheistic bent that includes other god-like beings. They live as one with the land, have a relatively primitive society, and are isolated.
Reachmen don't revere nature, and even desecrate it by worshipping Daedra nd practicing dark magics. They're tribal, violent, and traditional.
Ashlanders are nomadic, tribal, live of the land, and practice a more traditional faith of ancestor worship.
I really think Ashlander is the most Native American culture in Tamriel. Followed by Bosmer.
No race in TES is similar to the Indigenous people of the Americas, unless you consider the Bosmer. But that one seems to stretch it quite a bit. From what I know, only the Nords have a cultural system that is based around praying to, and considering animals as equals.
So if anything, the Nords.
But for the hell of it, just go with a Redguard.
Honestly there is none, Bosmer culture is pretty advanced, well they're a bit more civilized than the Orcs.
If you're trying to keep it lore friendly you HAVE to go as dark skinned breton Forsworn. You don't really have to stick to the armor when you get better stuff but you NEED the tribal tatoos.