OP you have pushed back and rejected all suggestions, which means that it will continue as it is.
So go back to why you posted in the first place.
You are fed up with how it is, and want something to change.
One thing you can do.
When her current run at the theatre is finished, let her know that you can no longer drive her to rehearsals.
She will need to pay for taxis, (and therefore need to claim benefits or get a job) or move closer to the place where the theatre is.
Yes that make mean she has to stop with the theatre for a while. And yes, some people may be disappointed. But that is up to her, not you.
That will get a kick back from her. But it is then up to HER what she does with this information. You don't have to do anything further. Her life, her responsibility. Let go.
Another thing you can do is to change something around food and meals.
For example, say that it is lovely that she cooks, but because you like to eat earlier, you will feed yourselves on Mon, Wed, Fri and eat with her on Tues, Thurs, Sat for example.
So you are changing YOUR actions, not hers. That means she can do what she likes with the new situation. If she wants to cook daily, then meal time is 7 pm.
If not, then you continue to cook for yourselves.
The issue around her safety is finally up to her. If she chooses to run late at night, then you cannot stop her. You have to back off and let go, and allow her to make her own choices. She is an adult, and you are an adult. She is not a child or a teenager.