[2021] [Linux - Solus] No audio in game

FYI the only supported distro for this game is Ubuntu, so there may be limits on how much we can help here. TBH I had not heard of Solus until now!

Does this also affect CK2, HOI4, or EU4?

Please attach your Documents/Paradox Interactive/CK3/pdx_settings.txt .
From your Documents/Paradox Interactive/CK3/logs/ folder, attach system.log , error.log

Also in Steam please click on Steam-Help-System Info, and paste everything there into a text file and attach that here.