Decentralization means being everywhere at the same time. How are you going to do that? Because if it's in a data center, it's not decentralized.
I'm not sure I get what you're trying to say here. Are you suggesting that if the domain/UI needs to be accessed through a hosting service, it means that an exchange is not decentralized, so they should use IPFS or something similar? But that doesn't exactly mean being everywhere at the same time since you'll have to connect to nodes still. On top of that, logging in using a web3 wallet doesn't guarantee anonymity either. CMIIW.
You also need to realize that OP hasn't been active for months so it's possible that they abandoned this project already.