Some days ago I saw someone complaining about not using home-manager due to the annoyance of having to rebuild the system everytime a change was made on his dotfiles.
Anyway, I found a way to symlink your dotfiles from /etc/nixos/dotfiles to ~/.config/ by using config.lib.file.mkOutOfStoreSymlink, it reproduces the same behaviour as GNU stow but easier since you can just program it in a nix home manager module. Example on how I have used it with Niri:
Its very self explanatory but basically "niri/config.kdl".source = config.lib.file.mkOutOfStoreSymlink "/etc/nixos/dotfiles/niri/config.kdl"; means "symlink ~/.config/niri/config.kdl to /etc/nixos/dotfiles/niri/config.kdl"
You can also link a whole folder at once but if an app creates a file within the folder (like noctalia does for theming) then when you rebuild it will give you an error because "the folder is not empty" so that's why I link my individual config files.