The hubris of a man who has been building his own desktops for over 30 years...

I've closed the case, wired it up, and am downloading Devuan, just assuming the RAM, power, CPU, GPU, M2 disk, USB key and everything connected to motherboard will work.

When will I ever learn...

The stupid "Ugreen" keyboard/mouse splitter didn't work, which isn't a great start (even using USB C power for the sparkly keyboard, changing the keyboard to the dull one etc).