Furniture selection help

You need to post more pics of this room from every angle before anyone can give you meaningful help.

following

Look for a coffee table about the same size but lower, so the top is equal to or lower than the seat cushions. You could use a square or round one. Start with a light colored patterned rug that incorporates some of the gray and another color that you like. That will help you with pillow selection. We need more photos to help with the window. You also need a floor lamp or an end table with lamp if you have room.

Is the rug staying? And yes, more photos from other angles would be helpful.

The rug probably isn't impossible with sofa - in person, are they at all similar in texture? is sofa tweed / rough / heathered-casual?

One large canvas art a bit like this? I've read on houzz of a "tight palette" and you could have greys/ rug colors, lighter/ touch of wood floor color like here:

John Richard Modern Classic Ashley Sullivan When I Am King Acrylic Framed Canvas · More Info

Color Block Blue Art Silk Throw Pillow Covers 18"x18", Shades Of Teal · More Info

Richmond Hill Reno & Decor · More Info

Cool and warm [I don't think pillows in the gold/bronze work though] -

"Abstract Reflecting Lights " Hand Painted Canvas Art - Wrapped Canvas Painting · More Info

https://www.houzz.com/products/abstract-reflecting-lights-hand-painted-canvas-art-prvw-vr~113162509

Seeing this with small blue and blue-purple, I like this better [than adding rust-wood -- more sophisticated like the sofa seems... a touch romantic. Add informal pillow in that purpley color.

Maison Framed Oil Painting · More Info

Ombre Velvet Pillow, Blueberry, Lagoon, 12"x20", With Pillow Insert · More Info

https://www.houzz.com/products/ombre-velvet-pillow-blueberry-lagoon-12x20-with-pillow-insert-prvw-vr~132451682

https://www.houzz.com/products/maison-framed-oil-painting-prvw-vr~94551593

Almost think modern look [maybe dressier finish though like 2nd lamp] to echo dark simple window frame:

Variel Table Lamp, Dark Gunmetal · More Info

Camden Table Lamp · More Info

Rug something like this in pale grays and golds. You could have a touch of the warm ebony to the rug palette to tie in your floors.

Couristan Calinda Runner Rug With Gold And Silver Finish 51950747023076U · More Info

Curtains (Move the sofa a half a foot away from the window to let the curtains fall straight down) Place the rod very high.

Triad Gold Printed Cotton Twill Curtain Single Panel, 50"x120" · More Info

Make sure the center of all your art is at eye level, usually 57"-60" from the floor to the center of the painting or, if over the couch, about 18" from sofa back. All your current art is too high.

Pathway Art · More Info

With patterned rug and plenty of prints in the room, then a round glass coffee table, or two nesting round tables would be functional and attractive. Here's one with warm brown base that echoes floor.

Boa Coffee Table Walnut · More Info

It's fun to try. :)

Ribbon Scrolls Gray Art Silk 12"x20" Lumbar Pillow Cover, Silver Spirit · More Info

https://www.houzz.com/products/ribbon-scrolls-gray-art-silk-12x20-lumbar-pillow-cover-silver-spirit-prvw-vr~28268510