Earlier quoted context omitted.
I let my CPU fan do its default color changing rainbow, buuuut only because it's under my desk where I can't see it. If nothing else, I can quickly glance down there and see if the computer is powered on. AMD ships them standard with their Ryzen processors, I guess the market for enthusiast range parts has decided that we want RGB hardware. Personally I think case aesthetics peaked around the Antec P180 which looked…
desktop literally built into the desk top The Sun "pizza box" computer was like that.[1] You could just bolt a 1U rackmount server to the underside of a desktop. Or get a desk that's 1.75 inches thick, cut a hole of the appropriate size, and recess the server into it. There are lots of under the desk computer mounts, but I haven't seen a recessed one. [1] https://blog.pizzabox.computer/pizzaboxes/sparcstation/
Except without the glass top. Or perhaps glass with a very dark tint so that it looks black, but with sufficiently bright internal lighting you can see through it.
The easier and more likely version would be to make the computer fit in a normal desk drawer. Prefer that to a 1U on account of fan size as another commenter mentioned, but being off to one side instead of the whole desk surface has the benefit of not making the whole desk chunkier.