https://nix-community.github.io/home-manager/index.xhtml#sec-flakes-standalone
Find the shell path eg: which fish
Add it to /etc/shells
Change to the new shell chsh
# https://github.com/NixOS/nixpkgs/issues/121694#issuecomment-2159420924
"/etc/sysctl.d/60-apparmor-namespace.conf".text = ''
kernel.apparmor_restrict_unprivileged_userns=0
'';