I see people ragging on cheap Chinese DDR4 and NAND all the time, but anecdotally, they work fine.
The only issue I run into is during pricing. Lexar and Teamgroup SSDs are cheap, but brands like Ediloca, fianxiang, kingspec, etc. don't have any significant pricing advantage in my region.
As for Chinese DDR4, I haven't seen anything to suggest they have higher failure rates compared to other brands/countries. They work fine at JEDEC specs.
But what I do notice is it's extremely difficult to figure out who made it. The chips will have some barely legible number, and it's nearly impossible to find it in a product catalogue, let alone who made it.