On Linux-based systems, this error often stems from the game attempting to use native DirectX 11 features that Proton hasn't fully mapped.
If you use mods, one of them may be overriding or removing localization files. localization dx11.txt missing total war
Total War: Attila and Rome II rely on specific C++ libraries to parse text configuration files. If these are missing, the game cannot read dx11.txt . On Linux-based systems, this error often stems from