I think any system language going forward really needs three things:
1. Generics / templates
2. Destructors
3. Ownership
It is unfortunate that this only has the first one. There was a language called clay that had all three and kept easy integration with the C ABI, but it seems like that design has been lost.
Destructors and Ownership implies RAII and all the design and architecture that are assumed with such things. This is far from C semantics, and so out of scope for C3.
Any RAII language will be considered a C++ competitor, not a C alternative. None of Zig, Odin, C3 or Hare has RAII.