You absolutely can do that in C++ with consteval + template, what's more, you don't even need consteval, constexpr will suffice:

  #include <cstdio>
  
  namespace detail {
  template<size_t N>
  struct Capitalize {
    char data[N];
    constexpr Capitalize(const char (&tag)[N]) : data{} {
      for (size_t i = 0; i < N; i++)
        data[i] = tag[i];
      data[0] &= 95;
    }
  };
  }
  
  template<typename T, size_t N, const char (&tag)[N], size_t count>
  struct MyType {
    static constexpr auto capitalized = detail::Capitalize(tag);
    constexpr auto name() const {
      return capitalized.data;
    }
    T array[count];
  };
  
  int main() {
    static constexpr char hello[] = "hello";
    MyType<int, sizeof(hello), hello, 10> value{};
    std::puts(value.name());
  }

I'd agree that zig's comptime encompasses many of C++'s features, and I appreciate the approach they took to new features by way of builtins (like @typeInfo + @Type for reflection), but this is not a good example.

Furthermore, why is type traits among the list of features that you claim is subsumed by comptime? not only is that not the case, but type traits are not so much a feature of C++ as they are of its standard library, implemented using templates (a feature of the language).