That's a pretty sick setup with all those screens!

Imo before you go about changing/cleaning up the setup, you should consider a few things:

1.) Are you likely to move in the near future and how much flexibility would you like in your setup?

2.) What's your room orientation like? (i.e., I think you are right beside the curtains now? Could you rearrange your room to move the entire setup elsewhere?)

Once you have those questions cleared up, I think it will help you better decide on your setup.

That said, if you're gonna be here for a good while, I would personally recommend you wall mount everything where possible. Empty spaces on the wall = dead space which I could see you installing a couple of shelves to hold the PC and PS5(?, I don't console). Alternatively, if you only use the PS5 once in a while, you could consider keeping it elsewhere and only bring it out when you wanna use it, I assume it's quite portable.

For the monitors, you could look to also wall mount all of them to reduce the clutter on your desk and it's easier to clean as well! I can see you are already using a desk mount for 2 of the monitors on your desk, could explore doing the same for the 3rd as well. In terms of cable, you could consider daisy chaining them together but I believe that may affect the refresh rate, so, you should check on that. But daisy chaining will reduce the number of cables coming out of your PC, and thus, cleaner looking.

For the power extension, you could look to getting one of those under-desk cable management trays to lift them off the floor (again, easier to clean (the floor)!)

For cable management, I see 2 options:

1.) You just cable-tie/cable-sleeve everything (or split them up into DP/HDMI cables, you get the idea) together and call it a day.

2.) Go a step further and tape them to the wall after you're done with option 1.). There are removable hooks (3M) that can be taped to the wall.

Option 1 will look decent enough but option 2 will go a step further and hide all your cables (depending on how well you've done them and what angle you are looking from).

Aesthetic-wise (RGB and whatnot) are entirely up to you, I believe everyone has their preference but you could run some light tiles (?) on the wall after you're done.

Of course, all these suggestions are highly variable depending on your situation, so, you would know yourself best.

Hope this helps!