[2023] I can't launch the game anymore

You can try uninstalling Paradox Launcher V2, and then starting the game via Steam, which will redownload the launcher.

In the launcher itself, in Settings, Video, set your Video settings to borderless fullscreen or windowed, this sometimes also fixes this issue.

If neither of these things work, go to support.paradoxplaza.com and open a ticket. Customer Support will be glad to help you out with this!