It's wildly inefficient, with those inefficiencies previously covered over by the former rapid rate of growth.
You can see that inefficiency coming to light now, as they over-invest into stagnant state owned enterprises in their credit markets and deprive the private market of capital. That despite most of the employment, innovation, and growth formerly coming from the private sector. The reason they're doing that, is to fake growth, the only place they can immediately force-allocate stimulus spending is in the giant stagnant state owned enterprises. Several years ago all of their economic metrics went hard south, despite their claims about growth everything was indicating a near recessionary environment, so they fired up big stimulus programs and inflated assets such as real-estate. That stimulus was overwhelmingly focused on things they didn't actually need and it has resulted in mediocre growth. They're facing the exact same situation again now.
Their productivity rate has collapsed since they shifted to that perma stimulus model seven years ago or so. Once your productivity implodes, you can only grow by shoving capital or labor at a problem. They have a contracting labor market, so their options there are now mostly exhausted. Which is why China now has to constantly run capital stimulus programs with big shots of capital or credit lending to the state enterprises. Their economy is no longer growing rapidly organically. Each subsequent round of this produces reduced returns, because the last thing China actually needs is to produce a lot more steel or concrete or buildings (they have extreme vacancy problems in their real-estate market), and those are the easy targets for juicing the economy in a command style from the top. It also resulted in loading up their local economies with enormous amounts of debt, as the local regions & munis are part of the stimulus shoveling process of moving capital into the state enterprises and real-estate.