Did you really have the problem that only launching from the launcher was broken, but launching eu4 from its installation folder was working?If someone would be so unlucky like post author or me, trying to find the reason why EU4 doesn't launch, the problem is multisampling in settings.
edit /home/*user*/.local/share/Paradox Interactive/Europa Universalis IV/settings.txt from multi_sampling=4 to multi_sampling=0