Here's how I see it: total depravity does not teach that we as God's creation are, at our core, bad. At least it shouldn't. What it does reflect is an awareness that somewhere along the way, a glitch entered the system: sin. Sin separates us from God in the sense that it harms the relationship we as humanity were meant to have with God, and it impacts our world deeply. Sin is a wound running throughout the flesh of creation, but what sin does not do is strip us entirely of the goodness intrinsic to our createdness.