> I want a computer where I can basically install every non stock app in its own little world, where it thinks "huh, that is interesting, I seem to be the only app installed on this system".
NixOS containers are the most convenient way to do this, but those will map the entire global nix store into your container. So while only one app would be in your PATH, all other programs are still accessible in principle. From a threat-modelling perspective, this isn't usually a deal-breaker though.
There's also dockerTools, which lets you build bespoke docker/podman images from a set of nix packages. Those will have a fully self-contained and minimal set of files, at the expense of copying those files into the container image instead of just mapping them as a volume.
NixOS containers are the most convenient way to do this, but those will map the entire global nix store into your container. So while only one app would be in your PATH, all other programs are still accessible in principle. From a threat-modelling perspective, this isn't usually a deal-breaker though.
There's also dockerTools, which lets you build bespoke docker/podman images from a set of nix packages. Those will have a fully self-contained and minimal set of files, at the expense of copying those files into the container image instead of just mapping them as a volume.