There are lots of ways to do this; pre-flakes e.g. you might have a root configuration file for each host which only includes other files, or have if statements

There are lots of ways to do this; pre-flakes e.g. you might have a root configuration file for each host which only includes other files, or have if statements. Nix flakes lets you define as many configurations as you want, and (if you don't specify one) will select based on the hostname.