Building certainty my Self and self-trust

Hi, I’m looking for resources to help me build certainty in myself and self-trust. I’ve been asked to take on new responsibilities in my work, specifically leading large zoom calls and conducting sales calls. I want to be more confident in public speaking, leading these calls, and in my sales calls. By that, I want to trust myself. I have a difficult time with being present and allowing for flow in these situations. I tend to want to over-prepare and control as a way to compensate.