I’m not a vet or anything, But I’d also create an array to tell you how many items have been created during each section. Because you have random amounts created you’d have to use guesswork to remove exactly what you need.
Having an Objects spawned array combined with the Obstacle ref array, you can use the objects spawned array to find out how many indexes to destroy&remove from obstacle ref array. For example you’d just run destroy actor and remove index 0 from obstacle ref array (objects spawned array amount of times).
You said you were having trouble destroying the actors though and none of those even cover that. How are you trying to destroy them?