[2023] EU4 Launcher on steam; click play, instant launcher crash [Linux]

Traps4life said: Steam (Flatpak version previously, currently Snap)

I think this is the problem. You'll need to install the Steam Linux client directly from their website:

Steam, The Ultimate Online Game Platform

Steam is the ultimate destination for playing, discussing, and creating games. store.steampowered.com "Install Steam Now"