Hi @jaduben
Good question.
That is correct the Zap step app account cannot be dynamically selected.
Believe you mean Task Comments, rather than Task Notes/Description.
From the Asana API: https://developers.asana.com/docs/create-a-story-on-a-task
Adds a story to a task.
This endpoint currently only allows for comment stories to be created.
The comment will be authored by the currently authenticated user, and timestamped when the server receives the request.
Depending on how many Asana Users you have, you may want to consider using Zaps w/ Filter conditions per User where the Asana Steps have the desired User account connected.
You’d have to authenticate each User account in Zapier here: https://zapier.com/app/connections