Proper reserve is a difficult question to answer for most of the satblecoin, how are they exactly backed, do they have billions of dollars on some bank account, do they have the paper for it on some vault? Do they have some digital numbers moving around from one place to another saying they are backed? Do they have bonds or gold or anything else worth that much? Do they have crypto that they bought with USDT which allowed them to be backed now but with a crash become not backed? There are a billion questions that could be asked about how they are backed even if they are backed.

Hence, I think it is not wise to use stuff like USDT, if you want fiat, go with fiat, if you want crypto, go with crypto, never trust your money with some stranger telling you that they have your money and will give it to you whenever you want, thats a shady business model from the start anyway.