It seems as though your rug choice, furniture stain color and fabric on the guest chairs are all warm. I think a grey would be a nice choice, but not sure about the Pier. I would need to see it next to the rug and furniture, as it might read a bit cold and dark with all the other heavy colors in the room. Sorry, I don't see the Juniper Ash at all. The Wasabi has a real yellow green undertone to me, not sure I see that with all the reds in the room. Your choice, of course, but I don't see sheers in the office. I would think panels alone, or perhaps matchstick or woven wood roman shades, would be a nice look. You didn't tell us what the flooring is, so I am thinking it might be wood. That matters in the color choice as well.

I think the desk is rather dated and if you can, I'd return it for something perhaps in glass, or something not so heavy. The desk should be compact and lightweight, which this one is not. How about a simple rectangular table which would serve a laptop very well. The office chairs are too big for the space. I would not put a run on top of another rug. If the other part of the room is a gym, small furnishings will look less crowded. You can achieve an office space without buying office furniture that is made for a larger, professional outside the home office.

Very helpful that you gave your pallet and thoughts. Choose your countertop and then your desk and cabinet colors. Countertop colors are limited, while paint colors are infinite. You can color match to Silestone Altair since you like that one - then go a shade darker or lighter for a nice color flow. Your pallet is very dark - except for the golden/beige walls- ranging from a black/brown to a brown/green. These are tones we used more in the 2000's so be sure and choose updated lines in the furnishings or the room will look dated already. The floor is beautiful! For the rest of the furnishings - choose a light colored rug, chairs in a beige or bring in a pop of a rich blue. Definitely add some greenery in natural stone pots on your shelving to bring in nature. A large, modern art piece would keep the vive fresh in this traditional space.

To hide cords, consider adding the equivalent of a "backsplash" to the desk but with a space between desk top and cords to disappear into so they can reach a multiple electrical outlet attached to the back of the desk. One plug from the multiple outlet will need to reach an outlet. Cords from desk top items will still be seen behind the items between those items and the "backsplash" They'll still be visible. If you drill holes in a solid "backsplash" board, you'd hide more of the cords. I've also seen basic desks with holes in the top of the desk at the back edge and the outlet hidden beneath the desk ... as this one appears to have: https://www.madisonliquidators.com/item/l-shaped-desk/4888/?adid=514792310094&gclid=EAIaIQobChMIiPO61aui8gIVFfjICh1t1QTwEAQYByABEgJt_PD_BwE Such desks usually have rolling filing cabinets or drawer/file units with shelves and/or drawers to set beneath the desktop by each side wall of the desk. https://www.harperoffice.com/onyx-mesh-open-mobile-file-two-drawers-15-3-4w-x-17d-x-27h-black--2?gclid=EAIaIQobChMImJysmKyi8gIVWsDICh2DzADJEAQYAyABEgIx9PD_BwE Others have storage built in as a part of the desk. https://www.wayfair.com/17-Stories--Sproul-LShape-Executive-Desk-X114267104-L32-K~W003156093.html?refid=GX528945859912-W003156093&device=c&ptid=910691620078&network=g&targetid=pla-910691620078&channel=GooglePLA&ireid=113112265&fdid=1817&gclid=EAIaIQobChMIiPO61aui8gIVFfjICh1t1QTwEAkYBiABEgIYMvD_BwE