I’m using nix-doom-emacs which allows a declarative doomemacs installation, unfortunately it’s currently kind of broken and we are stuck with a big drift with doomemacs upstream (pinned commit is this one from september 2022, issue to bump the doomemacs dependency is here and it’s not very active). It’s still usable though.

The creator of doomemacs is a NixOS user and he just uses the usual install process, so it might be the better way in the end.