As for the under-desk cable management, I took inspiration from this guide on YouTube.
For my own setup, I purchased this Cyberpower PDU for power distribution and this cheap mounting bracket to mount it to the underside of the desk, plus this StarTech 2x2in raceway for sleek-looking under desk cable management. Velcro straps, zip ties, and 3M adhesive cable straps were used liberally to organize and stick the cables under the desk to keep everything looking wire-free. When looking from the top, anyway.
I do embedded development on proprietary hardware for my day job, so I have a WFH mini homelab under my desk. Because of this, I can't eliminate all the messy free cabling under my desk entirely, unfortunately, but I sure do try.