See for example :
https://docs.synthetix.io/synopsisBasically you mint only a fraction of your collateral (typically 15%), so even a huge downturn of the price won't leave anybody hanging, and you provide a set of incentives for the owners of the collateral to adjust their staking depending on the price you are trying to follow.
It's not too complex, and seems to me way better than trusting tether and Co.