Seems there is no Asia/China in Clock setting.
Also if I select etc/GMT +8 the GMT offset change to -8.
Regards..
this is correct, don’t use this zone, it is not for China.
Because China is so big. You must use Asia/Shanghai or any other of the major cities based on this database:
https://en.wikipedia.org/wiki/Time_in_China#IANA_time_zone_database