Never thought of swap! Thanks for the improvements!
Now that this question has been properly answered - This is a very resource intensive task. As stated, due to the amount of physics and collision calls doing it this way would generate to spawn copies, you run the risk of turning your game into a slideshow. You can resolve this in a few ways:
A. Keeping this many actors only in memory by a struct that holds onto their transforms and a pointer to the static mesh they implement with collision and physics turned off, and setting up cull distance to cull objects out at a distance, which will also as a caveat freeze them in time, and most likely require a complex state machine to work correctly.
B. Put the task into Chaos, Cascade, or Niagara’s (depending on Engine version) static mesh options, for things like crowds, mobs, flocks of birds, bullets, etc. and do the draw/physics calls that way on the GPU. Keep in mind this also hikes your game’s base system requirements, and doesn’t make it accessible on Mobile devices, because the player needs a decent graphics card and most likely a PC.
It is up to you to explore your optimization options in this regard, as well as weigh the pros and cons of each. This is one task where it most definitely pays to learn some optimization techniques, and the options that Unreal provides for that.