What is the highest volume Dexes?

In the ever-evolving landscape of decentralized exchanges (DEXes), the question of which platform boasts the highest trading volume remains a pertinent one for investors and traders alike. With the proliferation of DEXes, it's crucial to stay informed about which platforms are leading the charge in terms of liquidity and user activity. Could you elaborate on what defines the 'highest volume DEXes'? Do these exchanges maintain this status consistently, or does the ranking fluctuate based on market conditions? Furthermore, what factors contribute to a DEX achieving high trading volumes, and how do these platforms ensure their sustainability in the long run?