-are there any decentralized stable coins that are superior to USDC?
In simple words, no. Because the liquidity and price won't be as close to where they should be with most decentralized stable coins.
-is DAI better than USDC since it's more decentralized?
I wish it was but the sad reality is that USDC is still better than DAI although USDC is centralized as opposed to DAI which is decentralized, but that's my opinion and I might be wrong. I am just comparing on the liquidity and market volume basis.
-Are there other decentralized Stable coins that are better than DAI?
Not right now but I am sure there will be in the future given how much concern is surrounding the decentralization of stable coins.
-Are there any projects coming in the future that I should keep an eye on that might have something that is better that USDC,TUSD,DAI, etc.
I am trying to find the same but quite frankly, I won't be touching any news coins unless they build a decent market cap or at least volume.