Hi, I am Dave, I will help you with this.
Windows and many of the applications installed on your PC are multi-threaded, that means the main processes are split into smaller processes so they can run on the various cores on your processor, so one core does not become overloaded and bottleneck, that is normal on all modern versions of Windows.
Svchost alone will have 70+ versions running in the background for Windows processes, if you are seeing any other process like Rundll having many processes running, please provide a screenshot of that in Task Manager.