I have the same problem as the original poster. This includes:
- On launch, the game gets to either 5% or 30% on the initial loading screen, then it crashes and freezes the entire PC, requiring a hard - reset from the power button to recover. When the game crashes, the audio goes on a broken loop.
- I've tried changing the Stellaris launcher to full screen with vsync off and a FPS cap of 60. Didn't work.
- I've tried running in administrator mode. Didn't work.
- I've tried disabling fullscreen optimizations. Didn't work.
- I tried disabling the Steam overlay. Didn't work.
- I have never run mods.
- I also experience RGB lockup with my keyboard, mouse, and PC components like the original poster.
Looks like I have a similar build to the original poster: CPU - 7800X3D, GPU: RTX 4080

SOLUTION: The solution that finally appears to have worked for me is to add < -opengl > in Properties -> General -> Launch Options for Stellaris in Steam (see image).