Yes you need color, a blue wall color to bring bring out the the blue in the artwork behind the sofa. Do large swatches and view the colors first. Look for a a pair of table lamps with a larger shapely base..ceramic and perhaps in the teal or blue color. I would lose the floral pillows with the white ground. The are too light and weak against the heavy dark leather. Get a much larger area carpet with some pattern. Look at pottery barn or restoration hardware for carpet inspiration and chenille pillows.

I like your idea of teal as an accent color, and for your walls I would select a light tan or taupe such as Sherwin-Williams Softer Tan or Wool Skein.

Behind your sectional, I'd swap out the end table and table lamp for a floor lamp. Your art over the sofa needs to be lowered to 5" above the sofa. The piece of art to its right either needs to be part of a grouping of 3 or more pieces with the one over the sofa, or moved somewhere else where it's not competing for attention with the other piece.

Your floral pillows, as you probably realize, are not right and need to be replaced with ones in the colors of that piece of art above the sofa. Good sources in the US are West Elm, CB2, Z Galleries, and others.
Carolyn Albert-Kincl, ASID

I wouldn't mind seeing the walls blue. This color, paired with leather, is baby seal/Dunn_Ewards.

Trade wind by Sherwin-Williams is another nice light blue/green to follow up on judyg's excellent suggestion.

Thanks, Carolyn