Are you using a cloned environment or the base environment? That would make a big difference.
The python executable is located in
'C:\\ ... ... ... \\bin\\Python\\envs\\arcgispro-py3\\pythonw.exe' # ---- use >>> sys.executable
Where ... ... ... is the folder that ArcGIS Pro is installed in.
I always install it in a folder I create (eg. C:\arc_pro) rather than letting "it" install itself where it wants.