honestly, it is not just the trading volume that I consider in choosing an exchange. I am also not certain to connect my wallet directly to the dex exchange, though I have the private key, the regulation, and convenience that a centralized exchange is what I want to consider. Most of the time, the volume in DEX is determined by traders, and it might not be the reason why people don't want to trade in DEX since the volume can be achieve if the crpyto do really is performing well in the market. It is the regulation that centralized exchange provides, despite of wallet security or also known as "not your keys, not your coins".