I use home-manager to manage most of my dotfiles and store them in a git repository. Additionally, I just symlink the configurations I'm too lazy to write as home-manager options (yet), which in turn is a decent way to make migrating to home-manager options less upfront.

NixOS. I've gotten so used to the declarative nature of NixOS, that I simply cannot go back to a "normal" distro anymore.

I used to use Determinate Nix on Pop!_OS before I switched to NixOS for good. You can still get a lot out of Nix on a traditional distro, granted you have to deal with few things manually (nixGL being one of them). But it still works, especially for development; it's just unparalleled.