I would say sway for Wayland support. Better yet, Hyprland is an awesome one and well supported in Nix. Maybe disable animation to reduce memory usage

With a SOC like that, that no way will only serve as a NAS, i can see my self easily hosting a dozen container on it and a couple VMs. That said, 12Gb is quite sufficient for my need.

Thank you

Maybe you might find home in one of those NAS ootimized distros like Openmediavault, truenas, unraid. If not CasaOS or old good Debian with portainer.