I'd be interested in any more info you can provide. Do you have your router configs in flakes? I'm currently testing Nix in a proxmox VM.

I just finished writing a shell script to dump all the UCI config files to one text file using curly braces to bracket/separate each file with the intent of committing this to a repo. Then will be writing a little parser to chunk up the text file to the appropriate /etc/config structure that OpenWRT expects. So at any point I can then just checkout different git branches, run the parser, and bam the entire config has been written to the router over ssh.

Still trying to figure out if OpenWRT has some other state outside of the /etc/config directory.