That's a brilliant idea but one shouldn't put all his/her eggs in one basket also OP may have a tangible reason to want to convert all the money into stable coin and my pick is DAI stable coin, it's decentralized and that makes it more reliable
If only to rely on stablecoins, then the choices are endless now, firstly the OP can look at USDT, USDC and BUSD which all of them already have quite a number of pairs with several potentially well-known Altcoins in the crypto space, so it doesn't have to be just DAI