55k usd is not bad in China. Silicon Valley is prob paying 100-150k for fresh grads at the better companies.
$55K in China is pretty good compared to $100K in Silicon valley, where housing is insane but not comparable to $100K in another city like US like Dallas, Houston, Chicago... Compared to Silicon valley, Shenzhen is cheaper living, food, entertainment, and travel (i.e. to SEA)