I want to leave my hometown, find a quiet small city to live, work for myself, support myself and live a quiet life. I don't know which place in China is good.

Every city has people who have lived a fast-paced life and a dull life. If you just want to leave home for a walk, you can choose a place not too far from home and go home whenever you want. If you want to do something outside, first go to a second-tier city to get used to it, and then go to a bigger city when you have some savings. At least make sure that you can live a carefree life even if you can't find a job temporarily, otherwise you may have to worry about eating before you start enjoying the single world. I hope it helps you.