Turns out the repair during build code path is poorly tested and causes errors. ref: https://discourse.nixos.org/t/error-getting-attributes-of-path-when-using-my-substituter/80448
To-do
Perhaps use overlay for /etc for speedup
system.etc.overlay.enable = true;
Performance for mini pc
security.pam.loginLimits = [
{ domain = "@users"; item = "rtprio"; type = "-"; value = 1; }
];