Competence is confidence with receipts.

Confidence without evidence is a claim. Competence is the same posture with a history behind it, which is why it holds up under questioning and does not need to be maintained. The receipts are what make it possible to be uncertain out loud without losing anything.

Build the record rather than the manner. Do the work, keep track of what you have actually handled, and let the confidence follow from that rather than preceding it.