it should just work with KDE

i have made a stl of that if you need the cable, it is janky but it works

Does it have the weird rj50 (yes 50) endpoint ?

Yes you have the kernel in the SD card and the root on usb

Since its GPU has composite out, why not a cool arcane cabinate?

Usually adding a slash at the end works if the protocol is http based

nothing as home does work (meaning plain hostname) works by default on openwrt dns

Raid5 (well raidz1) has saved my ass multiple times. Just dont forget to also raid your efi and swap partitions