I think the black sections on the red of the MCU Spider-Man suit are fine, it the tech lines on the blue sections that look bad and are unecessary.

The problem with having mechanical webshooters is it causes an inherent streamlining problem as you cant have the webshooters be below the suit as it will inevitably cause a visible bump (unless you make them vambraces that reach to the length of his red gloves where the red meets the blue), and so putting them over the suit and adding black sections helps integrate them more into the design, but the lineson the blue parts is just not required.