Coming across as confident for business success

I got the feedback that I seem insecure when I talk in front of people and/or on camera and I think the same if I see myself on camera, even if I do not really feel insecure. Now I realised that I have some belief around “If I come across as self confident, I get punished.”
I really want to come across as more convincing and self confident in my business because I’m convinced this will leverage my business and that successful business owners need to come across as confident. (Just another belief?) Though the insecure behaviour I’m showing in front of people/on camera happens so fast, I only realise it in retrospect. How can I change my behaviour when I catch myself only right after?