I recently read the answer somewhere and, while I can't give adequate credit to the author for I don't remember who it was, I can at least share it with you.
"To be humble, don't think less of you,
but think of you less instead"
It isn't necessary to think less of oneself in order to be humble; no need to devalue one's worth.
Instead, it's how often we think of ourselves that erodes humility.
Simple. To be a humble, yet confident leader just consider others more often every day. Yes, I have gone deep this time.