[2021] Red Triangle Error

That error is caused by bad or missing Microsoft DLLs.

you may feel you've done this already but go through this list carefully and tell me what happens with each one of these 6 installers, please:

Download Microsoft Visual C++ 2010 SP1 Redistributable Package (x86) from Official Microsoft Download Center

www.microsoft.com

Download Microsoft Visual C++ 2010 SP1 Redistributable Package (x64) from Official Microsoft Download Center

www.microsoft.com

Download Microsoft Visual C++ 2015 Redistributable Update 3 RC from Official Microsoft Download Center

www.microsoft.com

Download DirectX End-User Runtimes (June 2010) from Official Microsoft Download Center

www.microsoft.com (run dxsetup.exe after extracting from this download)

The latest supported Visual C++ downloads

This article lists the download links for the latest versions of Visual C++. support.microsoft.com And run the x86 and x64 installers there.  

BigMundo said: Not sure if you're still having this issue but I tried all of the above and nothing worked for me and then I uninstalled the paradox V2 launcher and then when I launched again through steam this redownloaded and booted up no issues.

Search: Add or Remove Programs -> Paradox Launcher v2 -> Uninstall -> Launch Steam -> Run Stellaris -> Allow this to redownload.

Worked for me so maybe will work for some other people as well but I did follow all the steps so maybe this also helped.
Not sure but I feel there is possibly an issue with the launcher that is causing this from at least my experience.

Thanks, but I don't think you can have been having the 0xc00007b Windows error like the OP, as that is a game/Windows issue and cannot be resolved by a launcher reinstall.