Cubase 10 performance vs system performance

Hi everyone,
I would like to know if there is a relationship between the cubase audio performance bar and the windows task manager.

I ask because I never understood why, with a fairly complex project that requires 75% of cubase resources (when it is stopped), in the windows manager the total use of the CPU is only 20%. When I run the project instead, I have: cubase> 95% (can hardly play) and general CPU performance around 30%

Is there a way to take full advantage of the processor’s potential?

I have cubase 10 pro, scarlett 6i6, i9 9900k processor with 64GB of ram on windows 10

Thank you