#I have a solid baseline because I like learning about history so don't do this like. Full research process every time. It's just the gist

[serpentface]

how do you come up with the ways cultures in your setting stylize people/animals/the world in general in their artwork, i.e. jewlery, rock carvings, statues, etc? Each culture in your world seems to have a very unique "art style" and I love it a lot - makes them seem that much more 'real'. This is something I struggle with a lot in my own worldbuilding and I'd love to pick your brain if possible 😁

I think a starting point is to have a research process based in the material realities of the culture you're designing for. Ask yourself questions like:

Where do they live? What's the climate/ecosystem(s) they are based in? What geographic features are present/absent?

What is their main subsistence method? (hunter gatherer, seasonal pastoralist, nomadic pastoralist, settled agriculturalist, a mix, etc)

What access to broader trade networks do they have and to whom? Are there foreign materials that will be easily accessible in trade and common in use, or valuable trade materials used sparingly in limited capacities?

Etc

And then do some research based on the answers, in order to get a sense of what materials they would have routine access to (ie dyes, metal, textiles, etc) and other possible variables that would shape how the art is made and what it's used for. This is just a foundational step and won't likely play much into designing a Style.

If you narrow these questions down very specifically, (ie in the context of the Korya post- grassland based mounted nomads, pastoralist and hunter-gatherer subsistence, access to wider trade networks and metals), you can direct your research to specific real world instances that fit this general idea. This is not to lift culturally specific concepts from the real world and slap them into your own setting, but to notice commonalities this lifestyle enforces - (ie in the previous example- mounted nomadic peoples are highly mobile and need to easily carry their wealth (often on clothing and tack) therefore small, elaborate decorative artwork that can easily be carried from place to place is a very likely feature)

For the details of the art itself, I come up with loose 'style guides' (usually just in my head) and go from there.

Here's some example questions for forming a style (some are more baseline than others)

Are geometric patterns favored? Organic patterns? Representative patterns (flowers, animals, stars, etc)? Abstract patterns?

Is there favored material(s)? Beads, bone, clay, metals, stones, etc.

When depicting people/animals, is realism favored? Heavy stylization? The emotional impression of an animal? Are key features accentuated?

How perspective typically executed? Does art attempt to capture 3d depth? Does it favor showing the whole body in 2 dimensions (ie much of Ancient Egyptian art, with the body shown in a mix of profile and forward facing perspective so all key attributes are shown)? Will limbs overlap? Are bodies shown static? In motion?

Does artwork of people attempt to beautify them? Does it favor the culture's conception of the ideal body?

Are there common visual motifs? Important symbols? Key subject matters?

What is the art used for? Are its functions aesthetic, tutelary, spiritual, magical? (Will often exist in combination, or have different examples for each purpose)

Who is represented? Is there interest in everyday people? Does art focus on glorifying warriors, heroes, kings?

Are there conventions for representing important figures? (IE gods/kings/etc being depicted larger than culturally lesser subjects)

Is there visual shorthand to depict objects/concepts that are difficult to execute with clarity (the sun, moon, water), or are invisible (wind, the soul), or have no physical component (speech)?

Etc

Deciding on answers to any of these questions will at least give you a unique baseline, and you can fill in the rest of the gaps and specify a style further until it is distinct. Many of these questions are not mutually exclusive, both in the sense of elements being combined (patterns with both geometric and organic elements) or a culture having multiple visual styles (3d art objects having unique features, religious artwork having its own conventions, etc).

Also when you're getting in depth, you should have cultural syncretism in mind. Cultures that routinely interact (whether this interaction is exchange or exploitation) inevitably exchange ideas, which can be especially visible in art. Doing research on how this synthesizing of ideas works in practice is very helpful- what is adopted or left out from an external influence, what is retained from an internal influence, what is unique to this synthesis, AND WHY. (I find Greco-Buddhist art really interesting, that's one of many such examples)

Looking at real world examples that fit your parameters can be helpful (ie if I've decided on geometric patterns in my 'style guide', I'll look at actual geometric patterns). And I strongly encourage trying to actually LEARN about what you're seeing. All art exists in a context, and having an understanding of how the context shapes art, how art does and doesn't relate to broader aspects of a society, etc, can help you when synthesizing your own.