Gaza has a sizable coastline, and China has a large number of amphibious assault ships available. They can defend themselves against Israel air attacks. If China decides to send humanitarian relief to Gaza, China can do it, and Israel can't stop them.[3] China would look like the good guys. Which their leadership knows.
[1] https://www.foreignaffairs.com/china/chinas-game-gaza
[2] https://edition.cnn.com/middleeast/live-news/israel-hamas-wa...
[3] https://www.newsweek.com/china-amphibious-assault-ship-type-...