How does POKT Network work?

Could you elaborate on the operational mechanisms of the POKT Network? I'm particularly interested in how it facilitates the decentralization of data access and retrieval for blockchains. Does it rely on a network of nodes that provide relay services? If so, how are these nodes incentivized and how does the network ensure they are reliable and trustworthy? Additionally, how does POKT ensure scalability and performance as more blockchains and applications adopt its services? Lastly, what are some of the key challenges POKT faces in its quest to revolutionize data access for decentralized applications?