In terms of the DSL, I’m really surprised that people find it a problem as much as they do. When I first tried Nix I moved my first nonprod server over to it that very afternoon. It helped looking at the syntax to start with as “hmm this is a bit like JSON” and to worry about things like lazy evaluation later on. I guess it helped that I was familiar with JSONNET beforehand so maybe that helped.
My first few servers I got by with just a basic understanding of the language and copying/pasting examples from the website and using https://search.nixos.org/options
Using on a desktop, now that is a whole other experience. I personally quite enjoy it for my desktop but there is definitely more of a learning experience and you might not find the benefits of Nix worth it anyway as your desktop is an always changing environment.