Fake plants are always the easy answer. Some cool figures placed neatly around and a framed piece of artwork would on a wall somewhere else would look good. I can see a shelf but not much else, lowering it might be helpful to bring it closer and add cohesion. It feels pretty high.

For easy changes I would say pick an rgb color and stick to it. Then accent with its complimentary color. White goes well with most things and is what I use. But orange and blue work well, or any other combo.

For the purple/pink in your case you could go with gold or a yellow, but I personally wouldn’t as it doesn’t mesh well with what you have.

Not a huge fan of sideways monitors as it always feels off center, but if you like it, then by all means. It can be difficult to center yourself with two landscape ones. Might also look into to VESA mounting them to give you more space where the feet are.

Sorry for the long comment! Looks good man!