Discerning between the client and dedicated server in the taskbar when running both on the same machine is difficult.
Even on a 1440p screen with upscaling the S is still barely visible, in fact I only just noticed the icons were even different while writing this cause the screenshot below is zoomed in.
A colour shift across the entire logo, similar to how the gmod dedicated server is orange instead of blue.
From an artistic instead of utilitarian perspective, replacing the icon with another celestial body in the same art style could work (the moon is probably the best fit, given it's close to earth but still distinct).