Just what I thought. After researching the two coins ( usdn and dai) I found out that they are similar to ust in which they are also algorithm based and that would be the main reason on why those coins fell down
I don't know if you know about DAI, but there is a difference between DAI and DEI. DAI is great and it has been therefore a few years. DAI is the only "fully decentralized" stablecoin know as of now