Why do the hard jobs still make me doubt myself?

You can wire a standard job with your eyes closed now. That part isn't in question anymore. What stalls you is the job with no clean answer — the panel that doesn't match the plan, the call only you can make. That hesitation isn't weakness. It's the gap between what you were trained to do and what no one can train you for — judgment. Every electrician who's good at this crossed that gap by making calls while unsure, not by waiting until sure. You're not doing this alone. You have a crew, a partner, people who've made this same call before you. Use them. The fastest way through the gap is to make the call, say your reasoning out loud to someone, and let the job teach you.