[2023] The launcher does not start, at all

Please try this:

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

Delete the following folders if still present:

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

- exit the Steam app entirely
- 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/{userName}/AppData/Local/Paradox Interactive/launcher-v2/
Please attach them here.
To see the AppData folder you'll need to enable View Hidden Items in File Explorer.

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

GenosseAnime said: I have already deleted and cleanly reinstalled the game 5 times

Doing that will not touch the launcher, as they are separate apps installed in different places.

2023-06-19T02:36:14.464Z (pid:14128) error [main]: GPU process crashed: undefined undefined

That does not look good!
DXDIAG is a program you run from the Windows search box on the task bar. 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.  

Kraden1602 said: I have the exact same issue with Stellaris, attached the logs and hope it´s okay to add my log here.

Thx

Actually you don't have the same issue, as you do not get that GPU error and you get a cpatch.log whereas the OP does not. Please make your own thread in the Stellaris Tech Support forum, thanks.  

The launcher will probably be running on your Intel UHD video system rather than the nVidia. That is normally okay as it is not a very demanding app, but perhaps that is a problem in this case.

Run the nVidia Control Panel app, manage 3D settings, and force C:/users//AppData/Local/Programs/Paradox Interactive/launcher-v2.2023.8.1/paradox launcher.exe to run on the 'high power nVidia" option there.

Does that help?  

You've gone into C:/users/{UserName}/AppData/Local/Paradox Interactive/ , you need to go into C:/users/{UserName}/AppData/Local/Programs/Paradox Interactive/ , with Programs in the middle.