Nowadays the OS means far less to me than my windows manager. I use nixos because I like the fact that I can see and configure the state of my machine in a few text files, but that does not give me a huge productivity boost.

Like the OP I use i3, and every time I have to use Windows or macOS I feel like I'm using a crippled machine. If I could put i3 on Windows or macOS, then I'd happily switch. With brew or wsl I really wouldn't notice much of a difference, given 90% of my day is spent in emacs, a terminal or a browser.