Chinesium is a term used in the West for low-quality products, especially given its association with China. However it should be noted that the reason for the low quality is because demand has outpaced supply thanks to consumerism and planned obsolescence. Manufacturing large amounts of high quality goods is both unfeasable and unsustainable when it comes to profit making as the products will be kept longer and will have to be obsolete in one way or another. As such they have deliberately downgraded the quality in order to save costs and manufacture more thus meeting this artificially high demand. A culture of frugality produces quality.
The association with China comes from so many companies outsourcing to Chinese sweatshops, allowing for prices to be lower than ever. In fact, had China not opened up to the world, we would not see Shein/Temu hauls - something I am more than happy to get rid of.