It's unlike most other Linux systems I've ever used.
The central idea is declarative structures. So your entire operating system, all of the apps and systems services and other custom things you need, are declarative in one place and hopefully easy to activate.
So instead of flatpak install, you add the program to a 'text file' and rebuild your system.
Everything is using the nix package manager which has been around since long before the distro nixos.
That's only the start of the rabbit hole, but if anything sounds interesting i encourage you to check it out!
How does your rust env setup look like? I've recently setup a full flake based dev-env, that uses fenix. It works great, but I'm interested in hearing a professional opinion