I've personally found a good compromise between using NixOS (without Home Manager) and classical dotfiles for home. My dotfiles are independent of the distribution, and also work in e.g. Arch.
I'm actually writing a script that takes my materialized NixOS-managed configs and backs them up in git so I can indeed port them to another distro if I decide to move away from NixOS (hedging my bets since NixOS is my 5th different OS/distro on this laptop).
Not having NixOS manage configs (itself or via HomeManager), though, very much reduces the value proposition of NixOS in my mind.
Not having NixOS manage configs (itself or via HomeManager), though, very much reduces the value proposition of NixOS in my mind.