These assistants could also be work-study students who are assigned a particular classroom (or digital space) or they might be volunteers from class who are given credit for assisting in the delivery of the course.
And of course, the first pivot (even in the same paragraph!) is exactly to these "free" or cheap sources which are likely to be overlooked and undertrained.
If a school is going to do this they need to take it seriously and actually give it professional resources.