Solution
Uninstall AMDVLK, you should probably use vulkan-radeon anyway.
I think there was a wine / proton update earlier today, I’ve just tried to launch the game from Steam and gotten the aforementioned message. I’ve found out that the message is common on Nvidia and Intel Arc GPUs but not AMD. I was wondering if anyone is now experiencing the same thing and if anyone knows a fix, I was quite looking forward to sinking another day into Starfield tomorrow…
No problem, I dislike it myself when I have an issue and there are no posts mentioning something similar or the OP deleted their post.
I also find it annoying when the solution is buried somewhere in the comments, so I make them as visible as possible.