Glad to know xfce has a kiosk mode, I wonder if it’s easier to set up than KDE or GNOME…

UFW definitely and maybe also selinux or apparmor to give internet access only to applications that need access!

I thought about Nix, it is indeed cool to declaratively install stuff and it would indeed be very helpful to set system settings all from one file so that you control everything there, but I don’t think that’s what I need, I think I’d need a more focused desktop environment maybe?

Kiosk environments could be a solution, because once the UI is limited, you can install software in any way you like and from any distro really, I think the focus is to keep it minimal under the hoods and very simple on the surface!