A stable coin is any cryptocurrency pegged to a stable asset, such as gold or fiat currencies. In theory, a stablecoin will remain constant in price, as it is a representation of a known amount of an asset.
My question is: Does a stable coin have a set total coin supply? Or does it have to be able to create and destroy based on the demand?
The image in my head goes like this:
A stable coin pegged to a currency started off its business saying it would have a coin supply of $5 billion. Everything works well until one day, the crypto market goes south and everyone rush to buy the stable coin. The coin is unable to sell to everyone because the demand for the coin is too high, so some people are left out.
Please correct me my misconception

simply applies the law of supply and demand, if a coin has a limited supply but the demand is high, it tends to increase in price, therefore not stable, if a coin has low demand, means it has plenty of supplies in the market, means no one is buying it, therefore unstable too, a stable coin has plenty of supplies and the demand is also high, volatility is the major issue here, the fast paced trading due to high demand and also growing supplies because of mining and panic selling on the market are the culprit.