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?
Try Curve, Aave, Balancer.
None of them allow you to stake because USDT doesn't have inbuilt staking, but they should all be able to provide decent returns that are much higher than what you would get from your local bank.
Also I would suggest that you swap USDT for another stable coin before you yield farm, because USDT is notorious for being fractional reserved.