Well, you don't have to have a standalone coin to get the features you desire. For example the AZTEC Network, which is a privacy protocol, can be used with any Ethereum-based ERC20 token, including algorithmic stablecoins like DAI, and soon Reserve.

A demo a couple years ago showed AZTEC being used to conduct privacy-protected DAI transactions for the first time:

https://twitter.com/avsa/status/1068536063470125056

Since then, AZTEC's privacy technology has become more efficient in terms of gas, and more effective at protecting privacy, going from protecting merely the privacy of amounts, to protecting the privacy of amounts transferred and sending/receiving addresses.

AZTEC is also developing a zk-Rollup, which increases Ethereum's maximum throughput from 15 tps to 3,000 tps, so that these private stablecoin transactions can be done at scale (though not 3,000 tps, since privacy comes with a computational and state storage overhead, but still much greater than 15 tps).