Yes, saying turks are steppe mongolians is silly although their initial origin or ascending branching comes from there. Like >>10405
said well (and i messed up) an origin can be from far away but the quick development into something else might happen elsewhere.
In that regard that part of the mongolian steppe, called by various names like Zhao, Slab Grave or Inner Mongolia, was home and origin to several sub-species with wildly distinct physical variations, from the grey, flat faced and absurdly squint-eyed korean and mongolians, to the orange and simian-looking turkic peoples who mixed a millenium later with iranians and other caucasians to produce the tatars, who also banged pajeets to produce the modern arab.
All this comes from a bunch of Xiongnu horse fuckers, they might be the ancestors but definitely not the original forerunners. Mongolia might be the origin but definitely not where they started miscegenating like crazy.