I'm looking for a way to stake stable coins like USDT or USDC off any cex exchanges, I know binance exchange allows staking usdt on its exchange but I don't want to stake mine on exchange but straight from a wallet that has private key instead, anyone familiar with any?
You can't just stake USDT, it doesn't have any inherent yield.
But what you can do potentially is put it on DeFi protocols and lend it out, for example Aave is currently offering around 6-7% on USDT depending on what the platform you are staking on is. I would suggest using MATIC given the low fees that you will come across.
Crypto.com has a DeFi wallet that you can use as well - but that is essentially automating the process of yield farming for you.