It looks like maybe a mix between Ainu (Indigenous Japanese) and Inuit (Indigenous Canadian/Greenland) leaning a bit more to Inuit for the most part. From the way they wear layered furs and it looks like they're in a mountainous region where it's wintery all year round, the boots etc remind me of Inuit clothing.
But you can see in Ignat's cave when Rita takes off his furs he has on kimono like clothing with geometric embroidered patterns that look a lot closer to traditional Ainu wear.
I also feel like I've seen wedding attire/headresses/earrings like Rita's that are simiar to a few different regions. The headress is similar to Wishram (Indigenous American) or traditional Palestinian wedding headdress, which use coins on chains with added beading, for example.
TL;DR: Seems like the artist researched and picked from a few different regions traditional clothing, and mixed what they wanted for Rita's people. I also like it, and this was fun to look into. I learned a lot! Thanks~
Does anyone know where are these clothes based of? They are beautiful so I’m curios