Besides japanese and thai idols that are established in the kpop scene and more are debuting, I can't remember the last time a chinese debuted. NingNing perhaps?
Maybe they are taking in vietnamese instead which we see are more than a handful in Kpop at the moment and Vietnam culture is kind of similar to China? Here are the ones active in Kpop:
--Beauty Box Anh(NUGU)
--Tempest Hanbin. Underrated and Hanbin is a popular former ex-Iland, so it helps the group awareness.
--Newjeans Hanni. A juggernaut group of Kpop enough said.
--tripleS Hsu Nien Tzu. Half taiwanese and half vietnamese, and former GP999. Yeah technically she is chinese, but Taiwan don't see themselves as China.
--Dong Ngoc Hai and Cong on BP999. The first guy is under Fantagio and I think regardless of his status in BP, he's likely will debut in Fantagio new BG.
--One of the trainees for SMNGG is vietnamese.
So you can see, despite being a market that is not profitable and not getting any visits by Kpop groups on tour, they are actually coming to Korea instead.