How much interaction do you plan to have between attendees? Consider the platform best suited to your requirements, rather than trying to make the square peg fit into the round hole.

If it is mostly one-way, essentially like television with a presenter and everyone else passively listening, occasionally with a raised hand and question, then a Zoom webinar is sufficient. I've used this myself.

But if there are to be multiple simultaneous subjects, you'll need breakout rooms or a different kind of tool.

Should people be meeting in pairs or small groups, rather than everyone in the same group...and you want them to have mobility? Apps like gatherly and gather.town let participants walk around as if they are on a city block or in a large room. As they approach other people chatting, the sound of that conversation picks up.

Do sponsors need booths? Airmeet might be the answer.

If you are going to be a presenter, perhaps the keynote speaker, then I strongly recommend hiring a master of ceremonies or manager to keep track of timing, segments, moving people to rooms etc. Your mind needs to be on being seen, not managing things. These are two different jobs.