That could be the worst carpet I've ever seen in my life. Gray would look nice, but would also require different paint on the walls.

Greige - carpet and walls may work with a shade of it. Stairs will be diabolical to change, I fear. Here's a tutorial.
https://www.houzz.com/magazine/going-greige-tips-for-choosing-this-all-around-neutral-stsetivw-vs~577375

Teal or seafoam green is a mid-90's look, and would not fit the mid-century architecture. But, if that is your favorite color, go for it.

Choose a neutral color for carpet. Otherwise you are stuck with that color palette forever or until you replace the carpet. Also really a problem for resale. Don't make the carpet the design inspiration. It is a vessel for other things. Have an inspiration piece for each room like a piece of art or overlay rug that sets the color palette for walk color pillows and accessories. Those things can be changed easily. No teal carpet ever anywhere nohow!