[Raion]

A certification from the Open Group means they paid them a ton of money to say "this is Unix". Anyone can technically do that and if you have a vaguely posix compatible OS with SuS-type setups, then it will probably get it.

UNIX is not a label you can buy though. It's a concept and lineage and macOS is a ukernel based on MACH, not a monolithic kernel with a lineage based on UNIX.

I draw the line at the kernel's design and lineage. They replaced the 4.4.BSD kernel with MACH for dubious reasons all the way back with NeXTSTEP, it lost any semblance of UNIX.

I don't consider Linux to be UNIX either for the same reason. I consider both macOS and Linux to be Unix-knockoffs.