They are having huge issues with e-bike fires in China. Here you have an article with two Chinese researchers weighing in on the issue.[0] According to them low quality batteries are the reason for the number of deadly fires.
So yes, Chinese ebike batteries are on a whole of low quality.
So yes, Chinese ebike batteries are on a whole of low quality.
[0] https://www.sixthtone.com/news/1013638