I modified the fan duct base of the BentoBox V2.0 to add a switch and nearly completely hide all cables.
See pictures for cable routing.
Also the holes for the threaded inserts where to big, so I sized them down to 4.1mm.
The lid is just snap fit.
There is also room for a step down module:
https://s.click.aliexpress.com/e/_DkqVZEr (Affiliate link)
Switch
https://amzn.to/3wof3wB (Affiliate link)
40x40x20 FAN
https://amzn.to/4a3w2Cq (Affiliate link)