Qt Creator not using all available cores for project parsing and running qmake

It looks like not all available cores are used for project parsing and running qmake.

For example, in a computer where there are 12 cores, all cores are used for compiling
but for other tasks e.g. project parsing and running qmake, only half of them (6) are being used.

See the video ( will be attached shortly) taken in
MacBook Pro 15-inch, 2018 running MacOS Big Sur 11.6
2.9Ghz 6-Core Intel Core i9 (12 logical processors)
32 Gb 2400 MHz DDR4
GPUs: Radeon Pro 560X / Intel UDH Graphics 630 1Tb HD

If all cores are used, could there be a possibility of speed improvement?