Yeah, do not use staging.
It’s pending Systemd 257 by jmbaur · Pull Request #356818 · NixOS/nixpkgs · GitHub to make its way into master (which will be merged from staging-next to master within the next week presumably). This happens via staging-next 2025-01-06 by vcunat · Pull Request #371501 · NixOS/nixpkgs · GitHub, and manual testing is generally done on the staging-next branch to verify that important packages are working as designed prior to the merge.
Status is available on the PR tracker https://nixpkgs-tracker.ocfox.me/?pr=356818 and you can switch over once nixos-unstable shows a checkmark.