That's part of what fixed it for me. What really fixed it was three things:

1. Actually being very knowledgeable about the subject in question, to the extent that I can offer facts or well-reasoned opinion on the topic on essentially any reasonable question. In other words, not being a junior high school student asked to do a 15 minute speech on a topic drawn from a hat.

2. Not having the idea that the audience expects a correct and immediate answer to every possible question.

3. Not doing every single speech literally in front of 15% of my entire peer group, including all my friends, all the people I admired, and all the people who treated me poorly.

I still hate doing Zoom calls without slides or a screen to share because I can't stand having 20 people staring intently at me. It's just distracting. But otherwise I have no problem at all talking for hours on a topic I know well.

Likewise, I thought I was bad at public speaking and avoided it almost entirely until my last couple years of university. By then I found myself surrounded by friendly, curious peers who were happy for me to nerd about whatever it was I became a semi-expert on. That confidence served me well once I needed to lead/train a team at work.

Doing a presentation on Zoom seems kind of pointless as you lose the connection to the audience. I'd rather just assign a pre-record to watch and do a live Q&A later on. More like a Lecture+Tutorial format.

One thing doctor, and to a lesser extent lawyers, have to do is project confidence when they may in fact not have much. A doctor/lawyer regularly has to quickly become an expert on a subject, or seem like one, often overnight but sometimes much faster than that. Briefing something you are still new to, without getting it horribly wrong, is a skill that must be developed.

I run into this in the military too. "The person to do the ethics/roe/safety/drugs/mental health brief just called in sick. Two hundred soldiers will be here at 0800 tomorrow. Read fast."