I don't know why you would need simultaneous transcription. You could get an electronic recording of an interview transcribed afterwards in a few hours at most.
Based on Caroline Lloyd's answer, I may have misunderstood what you wanted. Zoom will let you do the same thing she described, by using it simultaneously with otter.ai.
First of all, you need a team or a well focus and dedicated leadership to coordinate communities or selected groups or persons who would be factored for the interviews. Of course electronic recordings are required for a successful transcription.
To make it interesting and participatory through a coordnated one drive system.