Acting like you’re worse than you are to seem humble is still acting.

Talking yourself down on purpose is a performance with the same engine as bragging: both are about managing what people think. It also puts the other person to work, since now they have to reassure you, and after a few rounds that gets tiring. Real modesty is quieter than that. It mostly looks like giving an accurate answer and then changing the subject.

When someone asks how you did, try telling them plainly, good parts included. If you genuinely think the work was weak, say what was weak and what you would change, which is information rather than a bid. Save the self-deprecation for jokes, where it belongs.