[2021] something went wrong while updating the launcher

Please try this:

- exit the Steam app entirely
- uninstall Paradox Launcher v2 from the Windows "Apps and features" utility, if still present.

Delete the following folders if still present:

- C:/users//AppData/Local/Programs/Paradox Interactive/
- C:/users//AppData/Local/Paradox Interactive/
- C:/users//AppData/Roaming/Paradox Interactive/launcher-v2/
To see the AppData folder you'll need to enable View Hidden Items in File Explorer.

- run steam.exe as the Windows Admin user

- run the game from the PLAY button in Steam

IF that doesn't help, in this folder are some .log files:
C:/users//AppData/Local/Paradox Interactive/launcher-v2/
Please attach them here.

Note that you can run ck3.exe directly from File Explorer, which bypasses the launcher.  

Let's try forcing an update of the launcher.

Download the installer package: https://forumcontent.paradoxplaza.com/emailsignatures/2021.6-win-prod.zip

Unpack the file you just downloaded and place the three files in the Steam folder for the game you're having issues with. If asked if you want to replace already existing files click "yes" - that's a sign you are in the right place!

Then please repeat the launcher reinstall procedure from before.

Good luck with that!  

The launcher unloads once the game starts. But that happens with all games, not just CK3, so I'm really not sure what you are seeing there!