I know in Zoom, when you are the one speaking, the ipad speakers have no sound whatsover. This is the correct behavior, since if there was any audio (of your own voice in this instance), it would naturally get picked up by the mic and create an audio feedback loop.
Zoom does this automatically, and there is no echo. Basically, there cannot be any audio of your spoken voice in that same room (for example secondary devices connected to the same meeting must have their speakers off). Hope this makes sense, and something to check next time you try an app for conferencing.
The ipad mic is actually really good for this purpose, so there is no inherent hardware issue.