It was possible at least in older DisplayCAL versions.
1-Calibrate your display with default settings suitable for macOS desktop.
Now you have a single curve+matrix bpc profile AND a grey calibration for GPU
2-Reset DisplayCAL’s calibration tab all to native, so displaycal won’t correct grey, change profile type to a complex XYZLUT with the amount of patches you need.
3-Now calibrate & profile button should change to “Profile only” or something like that, and when asked check “use current VCGT calibration”.
So DisplayCAL will just profile you display AS IS, with current grey calibration loaded into GPU.
4-With complex profile created, just make sure you re-assign the simple “single curve + matrix” to display in OS settings.
5-Go to LUT3D creator standalone app in DisplayCAL folder, use the typical Rec709 gamma 2.4 (not rec1886) or 2.2 as source, use the new XYZLUT profile as destination, uncheck “apply vcgt” because it remains applied system wide with OS display profile