Maybe weird, but as NixOS user my dotfiles stay unmanaged. I VFS cache mount an S3 bucket using rclone(1) which gives the same home directory experience on all machines. Normally that would be something NFSv4 could provide, however the advantages of this setup are a) I can access HTTPs from most places without firewall issues b) takes just one binary.
I ultimately went with unmanaged dotfiles as well, it seemed like the most sane option. I host all mine on github so on NixOS machines I would just clone the repo and symlink to it as needed like I do on regular FHS systems.
(1) https://rclone.org/commands/rclone_mount/