This thread is the perfect example of useful idiots with astroturfing. This is a CPU core designed by UK company (and owned by Japanese) made in Taiwan on equipment made in EU (with non trivial USA components). Xiaomi here is the easiest to replace in this chain (and the Chinese have very much tried to replace any of the others, failing for now). Yet they are angling for a huge PR win.
Did they license an actual chip design from ARM or just the ISA?
ARM is merely an IP portfolio licensing company. They don't really design or build anything. And everyone uses TSMC (who uses ASML). The primary design is still being done by Xiaomi, that's the most unique part of this build.
Stop downplaying how big of an achievement this is.