[2020] My CK3 does not launch.

DXDIAG is a program you run from a command prompt or the Windows start menu 'run' dialog box (or 'search programs' in Windows 7 or later). After running it will open a window and start collecting info with a progress bar in the lower-left corner. When it completes click the 'save all information' button and save it to a file then attach that file here.

Please attach your Documents/Paradox/CK3/pdx_settings.txt .
From your Documents/Paradox/CK3/logs/ folder, attach system.log , error.log  

Kwisatz Haderack said: The files you asked for.
Error log is empty so it does not want to load.

The game appears to be running in Windows 8 compat mode, do you do that? Please undo it.

What happens if you exit the Steam app entirely and run ck3.exe directly from Windows Explorer?