Hi, don’t worry for about the late reply, as long as you get the right answer and solve the problem, I don’t care how long it takes 
So, to answer your question, I’m guessing when you put a destroy actor at the end, you didn’t assign the trigger you wanted to get destroyed, because if you did then it just simply had to work. Of course, unless some other script is messing around with you.
If you don’t know how to assign an actor, you simply drag it into your level blueprint from your world outline and assign it to the “target” in your destroy actor node.
Now, another approach I made when dealing with this, I used the DoOnce node. which basically does the thing exactly as it says, Once. After you put the OnActorBeginOverlap, you put the DoOnce node, and then the rest of the code continues.
I’m not that great in UE, but I’m talking from my experience, from how I did it in my project. I’ve come quite far with this project, and will probably be starting a dev log.
Please tell me if this helped you.