None of these things exist. There’s only stable (nixos-26.05) and unstable (nixos-unstable) channels for NixOS.
If you’re wondering about nix implementations, there’s nix, tvix, snix, lix, … I personally use lix for some quality-of-life features like better error messages and better performance in certain scenarios. Determinate system’s fork, I would argue, is barely nix since their daemon is an entirely closed-source rewrite with no plans to open-source it.