Cool!
Start with making a simple manager and see if that suffices, then add further layers if needed, always one at the time so you can easily track what actually helps (and what makes it worse).
Using Instanced Spheres instead of making them separate actors could help a lot as well.
Be sure to check if you’re optimizng right stuff. For example if I’m suggesting collisions - first try to disable all of the collisions and see if helps at all, before you try to optimize it. I’m talking from my previous experience, but every project and approach is different.