You can write Rust macros in Rust if you wish to do so, but it's a bit more involved (https://doc.rust-lang.org/reference/procedural-macros.html), btw

Rust also has const generics (but they are still a bit shabby in places last time I used them).

I for one never liked the constexpr semantic and syntax. Always felt like a... Little pebble in my shoe. Didn't quite annoy me enough not to use it since it was useful, but it was never a comfortable experience.