i think your making this a bit too complex for your use case. below i made a simple example of how you could handle your walls in a manner similar to a endless runner (since thats basically what your making). so at the most simple you need an endless stream of floors, this can be done two ways while actually moving the platform as you like. you could spawn new floors as they come on screen and destroy the old as they leave (many ways to do this). or you could just move floors and cycle them, so when one moves off screen you move it to above the screen and reuse it (better performance). ill be looking at the first method since its easy. for this method we will want to spawn a new room once something begins overlapping the current room, so if the platform is overlapping the room then we want to spawn the next one. for this we will need a collision volume (box), you will need your wall mesh, and to be used later you will want a scene component (i added a arrow to show placement). the actual script will be much like yours, on begin overlap spawn wall. in this case we add a little extra check to make sure the overlap isnt another wall to ensure it doesnt spawn more walls than needed. we also use a do once for the same reason, we dont want to spawn a wall bp for a overlap of the character and the platform. another little change was the use of the scene component to determine the new spawn location, this makes things much easier, versatile, and eliminates the need for the math your using. the last bit i included was a way to destroy the wall on end overlap, basically when the wall stops overlapping the player character we set its life span to 1 second meaning it will be destroyed in that amount of time. you may want to use a different method to destroy your wall sections since it seems like your looking to have exponential acceleration, you may need a variable lifespan or a different method.
personally i would incorporate the destroy into the platform and have that as its own bp actor. your platform could incorporate the camera as well then it would be easy to make a very modular setup to have multiple levels.
