By child actor I assume you mean as a child actor component?
I think it would help if you gave a more detailed description of what you’re trying to do since when it comes to performance there are a lot of factors to consider. I believe in general it’s recommended to minimize the number of components on an actor as there’s a processing cost associated with each. And for your case if both spawning as actor or child actor logically works, then what’s the need to spawn as a child actor if parenting is not necessary?