I grew up in Canada and have worked in China since 2015. Overtime definitely depends on industry, or more importantly a government job or private company. For government jobs, it is pretty lax. A lot of government jobs are usually 9:30am-11:30am, lunch break. then 2:30pm-5pm.
But private company jobs often have lots of overtime. And a lot of tech firms, design firms, finance or other service firms are infact private companies. In my case, as an architect, 50-60 hours a week is common.
However, I feel overtime in China is actually pretty unproductive, usually caused by needless bureaucracy, bad client management, and just unhealthy overtime culture. I remember this one time, I finished my assigned work from my manager and left on time because my parents came to China to see me. The next day I was reprimanded for leaving before the project group finished their work. I was stunned at this, since I was focused and finished early rather than doing “tea breaks” and chatting during work.