I think this is the current state, yes.
I think what's a bigger lift is, supporting "chat" with a prompt. That is not currently supported, and sounds like what you might really need. The prompt runner today will let you render it, and run "as is" with use input. You may be able to get it to trigger subagents in limited fashion, but you won't be able to "keep going" with the chat.
One point of clarification. You don't "see" it, but is the prompt able to delegate to the sub agents properly when you run it?