In most leftist circles, market socialism usually just boils down to wanting every business to be a worker co-op where everyone owns shares in the company, plus state welfare programs. I rarely see leftists refer to China as market socialist, what you tend to see is either it's supporters referring to it as "using market forces forces to build the conditions for communism to be transitioned to," or its detractors just calling it authoritarian state capitalism that merely pretends to be socialist.
Also, be careful about the term "corporatist/corporatism," as historically those terms don't mean "likes big business (corporations in the modern capitalist sense)," but rather refers to the fascist philosophy of the nation state, its labor force, and its economy as "corporate" in the sense of being elements of one shared body to be coordinated by the party as single social organism.