I was going to say “I would advise against that as a workflow”, but I think I understand what you’re looking for. If you’ve used Jira, this sounds like the Action buttons that move work from one status to another. You might be able to build something like that with App Components in Asana App components but I’ve only read the docs for that and haven’t built with it.
More commonly in Asana I would suggest having people move work to the next step in the workflow. You could do this in a few ways, either by having the user change the section the task is in or changing custom field value for a Status custom field you create.
That all said, I think this is what you’re trying to build and it avoids race conditions https://www.loom.com/share/9991640f49ed44e3904902b0d965a559 it’s the same concept as my other video. In the video Larry linked, my use case was form intake. You’ll need automation steps in between each work step. Just takes a little work to setup, but should avoid the duplicate subtask issues you are facing.