Often when I launch a game through Steam that “processing Vulkan shaders” window appears and loads for a couple minutes. Sometimes it takes no time, sometimes it takes several minutes. But then, for larger games like Dune Awakening or Outer Worlds 2, the game needs to sit and process shaders for another couple minutes anyway. But for some games, like Enshrouded, I can skip the Vulkan processing with no problems in the game (I do that because the Vulkan processing doesn’t go anywhere). So what is that Vulkan processing for?
The only times my shaders get recompiled is after a Steam game updates or I get a Linux firmware update. I usually run Steam on a second desktop after I boot and am planning to play games later.
I also have the System Info widget, running in the Taskbar on my main desktop, set to show CPU usage. When the CPU usage drops to near zero, I know at a glance when the shaders are done compiling. (It usually doesn’t take more than 5-6 minutes).