[2021] I cannot launch the game at all, no mods are installed.

CoffeeKitty said: as i said in the first post, that was one of the first things i've tried, directly launching executable does not help

and no sadly it does not work in any windowed, borderless, or fullscreen mode, vsync on or off.

Add stellaris.exe to the exceptions list of your antivirus app; ESPECIALLY if you have Windows Defender, add it to the Ransomware "Apps Allowed Through" list.

Also if you have FRAPS or the MSI Gaming App or Rivatuner installed, disable it as it clashes with this game.

If that doesn't help:
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/Stellaris/settings.txt and pdx_settings.txt .
From your Documents/Paradox/Stellaris/logs/ folder, attach system.log .