On any Linux system you can have no window manager (or an extremely minimal one) and just start a single application on login. It's been a while since I've don

On any Linux system you can have no window manager (or an extremely minimal one) and just start a single application on login. It's been a while since I've done that and most stuff has moved away from X11 now, but yes exactly what you want is possible. To log in and have nothing but a single application, no menus, no desktop, etc.