There is no decentralization.
As you mentioned, the token works just like usdt or udc, which are fully centralized.
Who decides what to do with the BTC lended? Who holds the BTC? Who holds the data to confirm if wbtc is or not backed up by BTC?
All these items and much more and controlled by one person or company, which makes your project fully centralized.
Your text is misleading imo. You are trying to advertise your service not the way it really is.
You should change title for like "earn interest by lending me Bitcoin" , for example. Because nothing is decentralized there.
You also said "trustless". How would it be trustless if users have to trust you have BTC pegged?
I agree that wBTC is not as decentralized as normal BTC due to the fact that only a select group of companies manage it. For each wBTC created, the custodian, BitGo as far as I'm aware, locks an equivalent amount of BTC into multisignature contracts. They do continuous audits on those contracts to make sure that the wBTC that exists matches the BTC stored in the contracts. Again, NebliDex is not involved in that process so we are not the custodians but merely an exchange between wBTC and BTC.