Looks a bit random. I don’t think you need to specify optimization level (it is like that for production already) or C/C++ flags (not sure why you have them there). Also native is not always the most performant, but will not hurt generally. Even if you don’t specify any of those environment variables, you should get efficient and performant build (though I would recommend main branch before the next release due to Fix AES-NI enablement by default, including when building container images by nazar-pc · Pull Request #2291 · subspace/subspace · GitHub)…
The command itself seems correct and should pick up rust-toolchain.toml if you installed Rust itself through https://rustup.rs/ and not OS’s package manager, that can have customized Rust toolchain with various “features”.