I mean, C++ have RAII and stuff like unique pointer, does that make it higher level than Zig?
And what if you don't use Arc or Box? Is your program now lower level than baseline Rust?
As I said, depends a lot about what you mean by low level.
C++ offers much higher level primitives out of the box compared to Zig, so I'd say its a higher level language. Of course you can ignore all the features of C++ and just write C, but that's not why people are picking the language.