Not just self confidence but also self-awareness because hacking is something that you can't be a victim of unless you somehow gave the hacker your information. There can be emails that contain phishing links or there can be brute forcing methods applied by hackers to gain access to your accounts.

What one needs to do is just set a strong and different password for each website/exchange and make sure to avoid clicking any emails they receive from unknown sources and verify the sender's email (sent-from).

I am also being in crypto since a long time but I never got hacked because these are basics and I was always aware of these.