But to be fair, Nix is not the only answer to that. There are lots of tools for just dotfiles but you can also build something using e.g. ansible to manage everything.
All my computers have their config in a git repo. That includes users, packages, services, dotfiles, /etc configs and so on. I used ansible before writing my own tool. I can install Arch from scratch and only need to partition, run one script and then apply my config on first boot using my tool to have my system restored. I know it’s not as declarative and absolute/reproducible as Nix, but it works and it’s way less painful than my last attempt at giving NixOS a go.
I would not trust any company/website to properly encrypt any important messages in the first place so I don’t care whether they add a backdoor (and I’ve never had a Twitter account anyway).
…but it sounds like a really shitty development/release process to me. Why would you disable something while whatever is to come in its place is not ready yet?
Why not do the development first and then migrate when it’s actually ready lol