How do you have high-level, expert-quality, discussions with a large, open, audience?
You can’t. You have to choose.
Do you want expert-quality discussions or the large audience?
People don’t like to feel dumb (or like frauds).
Most people participate in discussions where they can add their experience. If they don’t have that experience, they usually won’t participate. They might ask a question or two, but they won’t participate for the long-term.
If you want to be the biggest, you might have to be the dumbest. Which is a crude way to say you might want to focus on the beginner-level discussions that everyone can participate in. You might not advance the field, but you can help a lot of people progress through it.
There is plenty of value there. Just be clear about what you’re creating.
Alternatively, you can create a tribal knowledge base featuring the contributions of top experts that might define your field. You can build key relationships. Far fewer people will help create the material, but many might read it.
Just decide which you want.