1st post: "I booked the ticket and did the visa on arrival with the documents I had received from [edited]. I applied for 1 day rush and received my work visa the next day then entered China."
Now:

Z visa on arrival for Guangdong province, it started from last year and only works for
Guangdong province

On arrival where? Z visas only work wherever the employer that sponsored them is located. There is no such thing as a "Guangdong Z visa". Once you are IN the province, you are given a residency permit and a FES, NOT a Z visa. Z visas are only provided outside of the mainland.

If you received your Z visa in HK, please tell us your nationality so that readers are aware that HK is now offering Z visas for teachers of your NES country.

And if you had a Z visa, you should not be reluctant to identify the school.

If you fail to identify you country of birth and the school, you are a shill for [edited].