Background services are split up into more separate processes now, scaled based on the system's capability.
You would want to identify specifically what processes are using additional CPU. If you cannot see anything specifically allotted to a process, then the CPU time is likely being used by a faulty or bad driver. Audio Drivers, Graphics Drivers, and certain Network Drivers are sometimes responsible for that. Webb browsers and particularly say youtube videos can use up a good amount of CPU time as well, particularly for higher resolutions and/or if hardware acceleration is turned off.
However, I don't think your problem is related to having too many processes and handles. By way of example, Right now, I have 292 Processes, nearly 4K threads, and nearly 250,000 handles, but everything functions normally. and I don't see excessive idle CPU utilization.