I know my approach might be wrong, but please humor me a little.

I'm trying to do DialogueSystem where I can send a string to another class and have it
spit out words one by one through a certain t time.

public class Dialogue
{
	public Actor actor; //enum
	public string line;
}

public class DialogueSystemManager
{
	public static Func<Dialogue,bool> OnBroadcastToActors;
	Queue<Dialogue> sequence;

	.........
	//This class querries a Queue from a SerializableObject and sends it to a Coroutine
	public void GetQueue()
	{
		//Gets a queue from the SO
		StartCoroutine(OnBroadcastToActors(sequence));
	}

	//I want to send the dialogue one by one to the actors in sequence, thus the queue and dequeue
	//and wait for the coroutine in the other class to finish before continuing, thus the use of a Func
	private IEnumerator BroadcastToActors(Queue<Dialogue> _sequence)
	{
		for(int i = 0 ; i < _sequence.Count ; i++)
		{
			var dialogue = _sequence.Dequeue();
			yield return new WaitUntil(()=> OnBroadcastToActors(dialogue));
		}
	}

	.........
}

//This objects that need to talk have this class attached
public class DialogueActor
{
	public Actor actor; //enum //initialized on Awake()
	TextMeshProUGUI dialogueText;

	..........
	void Awake()
	{
		....
		DialogueSystemManager.OnBroadcastToActors += OnReceiveBroadcast;
		....
	}

	bool OnReceiveBroadcast(Dialogue _dialogue)
	{
		if(_dialogue.actor != actor)
			return false;

		StartCoroutine(ShowText(_dialogue.line.ToCharArray()));

		//Here is where I'm stumped. I need to wait for the Coroutine to finish before continuining here,
		//But can't figure out the best way. Maybe the use of a Func is not the best way?

		return true;
	}

	IEnumerator ShowText(char[] _lineArray)
	{
		dialogueText.text = "";

		foreach(char c in _lineArray)
		{
			dialogueText.text+= c;
			yield return null;
		}
	}
}