Yup, I too had issues with sound, the game seems to just use the first sound interface available, but it is relatively easy to change after starting (via KDE sound panel for me, but I imagine pavucontol should also work). The issue seems to be with Unity/FMOD on linux not the actual game. Newer versions of Unity seem to not have this issue and author was saying they are trying to see if they can upgrade.
PS I was attempting to make a pipewire LUA script that would auto connect the FMOD output to default interface but got stuck on querying and linking audio ports and interfaces, if someone has more Pipewire-Fu I am all ears!
PS I was attempting to make a pipewire LUA script that would auto connect the FMOD output to default interface but got stuck on querying and linking audio ports and interfaces, if someone has more Pipewire-Fu I am all ears!