[2020] Game Not Launching

In that screenshot we can see that a launcher update has installed, but you haven't restarted the launcher to apply it.

Please do that - does it now show 2021.6 ? or still an older version?  

If you can run ck3.exe directly but the launcher can't , this is usually a permissions problem.

Please right click on each of these, compatibility, and set them to run as the Windows Admin user:

ck3.exe and dowser.exe
C:/users//AppData/Local/Programs/Paradox Interactive/launcher-v2.2021.6/paradox launcher.exe
C:/users//AppData/Local/Programs/Paradox Interactive/bootstrapper-v2.exe

Good luck!