The muckraking blog For Better Science has been sounding the alarm on this for years. Here's a great investigation into a "paper mill industry"[1] which apparently this researcher also traced some of the fraudulent papers to. It gets into some of the economic forces that drive it.

P.S. scanned 130 million papers! WTF!

[1] https://forbetterscience.com/2021/05/26/the-chinese-paper-mi...