Hey, Spyfish! With the Razer Cynosa Chroma, I’d suspect the Razer Chroma low FPS issue is the cause. Toggling the Overwatch Chroma Profile, on and off, and if it continues, performing the steps on this post should address this concern.
The behavior we see with this is the spectator mode and menu are normal frame rates, but while in-game the FPS drops to anywhere from 10-30FPS.