To fix your streaming pool warning you can use “r.Streaming.PoolSize 1000” or set to a value until the error message stops showing.
If your camera doesn’t need to utilise much of the spring arm functionality (and a lot of it is best used in 3D games), you could opt to detach your camera component from your player and manually SetWorldLocation for the camera, on tick, using X as the location of of the player, Y and Z as the location of the camera.
If you want the camera to also follow the character upward, but not to a point where it will see outside of the level, you can use the character’s height value, and clamp it, (or map to range clamped) to whatever limits look good for your game, and use this as the height value for the SetWorldLocation.