It can be challenging, but never forget that Nix is a language, a package manager and an OS.
You can start with the package manager on the OS you already have (note: I went straight to the OS on a spare computer and a month later moved my config to all my other machines, portability and reproducibility is where Nix shines)
Once you have been inside the Nix rabbit hole, you can't to back 😉
Mainly Linux (and I prefer Gentoo), although due to laziness I still haven't reinstalled my new Thinkpad T470s travel laptop, it's still running Win 10 Pro and I use Ubuntu with WSL for development there.
I have a MacBook so I mostly use that but I use Ubuntu on my old laptops and my desktop. Also I have a full node running on Ubuntu on one of my old laptops