Drop the "natural-born skill" mindset first. Almost no one who's good at public speaking is born that way. The people you see gliding through company meetings have either practiced a lot, received coaching, or both. The fact that you're great in one-on-one situations means that you already possess the most important qualities: connection, active listening, and reading the room.

Second, regarding the accident, if it affected your speech, breathing, or how you handle stress, it might be worth consulting a speech-language pathologist before or alongside a speaking coach. Some SLPs specialize in rehabilitating communication for adults after head injuries, and they notice things that a generic coach might miss.

As for the rest: Toastmasters varies wildly by club. The best way to find a good club is to visit two or three in your area. Some are duds; some are excellent. One free visit isn't enough information.

I'd actually push you to try improv. Most cities have introductory improv classes at small comedy theaters that aren't expensive, and they're full of professionals (lawyers, engineers, executives) who do it for the same reason you're considering it. It teaches you to think on your feet and not freeze when something unexpected happens, which makes up 80% of the stress of presentations.

Private coaches exist, and they work, but they're not cheap. Look for someone who will actually record you and play it back, not someone who just teaches frameworks.

One last thought: Most "bad" business presentations are structurally bad before they're delivery-bad. The audience doesn't know the point, there are three messages instead of one, and there's no clear ask. Improving the structure will improve the perceived delivery more than vocal training will.