I come from Southeast Asia so the treatment is different (white privilege is extremely beneficial). Xenophobia is next to none. I managed to join a Chinese football/soccer team and badminton group.
I didn't apply for the job in China on purpose so can't help you on that. The difficulty of obtaining a visa sits on polar opposites. If your employer is a legit and big organization, you can get a legit one.
Others I met in Shenzhen just went with a business visa good for 30 days. This worked fine in this city since you can simply take a train to Hong Kong and reset your stay. Get a passport with more pages if you plan to do this.
Culture - most Chinese are very tolerant or don't care at all. I've heard other people say that Chinese are rude/impolite. You get used to it or get too tired of it.