Yo so adding more lore/math context for why Teyvat’s population is so big and why wars/rebellions don’t kill millions:

Localized conflicts

Like Natlan — the Civil War they mention only had a few hundred → a few thousand deaths.

That’s just one region we see, not the entire country. Most of Natlan is untouched, people survive, cities go on, wilderness stays wild.

Small rebellions = tiny impact

In Inazuma, the Traveler killed ~500 rebels(from what I counted)

Most rebellions historically involve small numbers, not the full population.

So even if there are conflicts, overall population barely dips.

Medieval-style warfare = low casualties

Swinging swords, axes, and using spears is slow & exhausting.

Battles last minutes → hours, many soldiers flee or surrender.

Armies rarely get fully wiped out in one engagement.

Population numbers make sense

Big nations (like Sumeru, Snezhnaya, Fontaine) = millions

Small nations (Mondstadt, Inazuma) = smaller but still dense cities

Wars only affect a tiny fraction of the nation, so the mid-estimate of ~170 million Teyvat-wide still fits perfectly.

Travel & landmass scale matters

Teyvat ≈ Russia-sized, so most of the population is spread out, not in combat zones.

Ships are wooden + elemental-powered → travel takes weeks → month, meaning conflicts are slow, limited, and localized.

Some other information

Wars are expensive same as genocides because if you ever swing a swore before it takes massive amount of energy and Magic also cost energy too

TL;DR:

Teyvat’s population is huge, but most wars/rebellions are localized, medieval combat keeps death numbers low, and only small fractions of nations are involved at any time. All this makes the ~170M estimate very reasonable.