I feel you. I’m a messy person by nature, but I find it hard to function in a messy environment. These two sides are constantly fighting each other. Discipline will help keep the mess at bay, and there are several tricks I use to bolster my discipline.
One trick with cords is to ensure that they are exactly the right length — which means buying replacement cords, bundling the excess neatly, or moving the excess under the desktop. And cables should run perpendicular to the keyboard, running straight back. Use cable clips to keep them in place (I like to put these out of sight unless I unplug the cable regularly).
I have mounted my power strip to the wall underneath my desk, as I find it easier to access. Most power strips have mounting holes for screws.
Putting things on the wall is always a good idea. This can mean directly mounting each thing, or you could put up a long shelf to hold the speakers and Mac Mini. Bundle the cables and cords along the back of the shelf and run them straight down the wall in a group (always being mindful of possible interference, of course).
If you don’t want to or can’t mount a shelf, then my next favorite thing is small shelving or risers to allow stacking. I can fit my scanner on my small desk because I found a riser that fits over it that will hold my Mac Studio and its Time Machine drive. I use another riser/shelf as a way to corral small stuff. Some of it is for active projects (I’m in the middle of swapping out my old external hard drives) and some is for daily use (pens, post-its).
My rule is that no junk can be on the surface of my desk unless I’m using it at the moment. Corralling the debris helps a lot!
Another thing to corral the junk is to use small and shallow trays. For example, on my wall shelf I have a stainless steel serving tray to hold jump drives, mints, stray pens, etc. It’s shallow, so when it gets too full the stuff falls out and I’m reminded to put the excess where it belongs.
Larger trays are also useful on the desk surface. I don’t have room for that, but your desk could hold one big enough for a sheet of paper.
Trays work better for me than boxes for me because once the lid is on, I forget about what’s in there. (This is not true for a box that holds specific tools, because I can remember what tools are in there. But for the daily-changing junk, a closed box is a coffin!) I don’t like stacking trays because the bottom one always ends up as a dead zone because it’s easy to reach. And, of course, a tray that’s too deep is an invitation to allow stuff to live there permanently — which is not good because my desk is not for storage!
Amazon has lots of various risers, but it can’t sort by size. That makes it tedious to use. Still, it’s where I started my search.
Once I decided that an acrylic riser would work for the scanner+computer, I found an online company that specializes in shop displays (https://www.shoppopdisplays.com) so it was easy to find a specific size and sturdiness.
Then I found a new product at Ikea (Vattenkar) to use under my monitor whose only fault was it was slightly deeper than I wanted. It’s working well for me, and the open back means the foot of my monitor slides under the shelf (many monitor shelves have solid backs).
I’m going to search my local thrift store for another stainless steel tray to use on the middle shelf to better corral the little bits and bobs. Those trays are usually easy to find, and they’re sturdy and inexpensive. I keep the bottom space open for keyboard storage so my kitten doesn’t walk on the keyboard and wake the computer (or start music playing when I’m on video call!).
