First thing to break down is that there are two main models of exchanges: decentralized and centralized. Depending on your references, you can decide on which model you would like to trade your assets. Technically, DEXs are more secure than centralized models as all transactions facilitated on DEXs are peer-to-peer and executed by smart contracts. There are no third parties controlling over the flow of your funds. DEXs could facilitate faster and less expensive transactions than any centralized models since there is no additional fee fixed by the third-party. You can try out HB DEX, they are 100% decentralized and the top 1 Ethereum wallet platform in Japan.