NixOS. Started with Yellow Dog Linux in 1998. I don't do *everything* through nix's derivation system. Many of my configs are just an outOfStoreSymlink to my configs in the same dotfiles repos. I don't need every change wrapped in a derivation. Neovim is probably the largest. A few node projects for automations I'm fine using pnpm to manage. Nix still places everything but I can tweek those configs and commit in the same repo without a full blown activation.