The issue here is with the location of the SteamNative library. If you can do some research and find out why it's not finding it, or why it's not loading it.. that will help me out a lot
That is what I get in my log when is start rust.x86 -logFile:
Fallback handler could not load library /home/xavier/.local/share/Steam/SteamApps/common/rust/rust_Data/Mono/x86_64/.//home/xavier/.local/share/Steam/SteamApps/common/rust/rust_Data/Plugins/x86/libSteamNative.so
Fallback handler could not load library /home/xavier/.local/share/Steam/SteamApps/common/rust/rust_Data/Mono/x86_64/lib/home/xavier/.local/share/Steam/SteamApps/common/rust/rust_Data/Plugins/x86/libSteamNative.so
Fallback handler could not load library /home/xavier/.local/share/Steam/SteamApps/common/rust/rust_Data/Mono/x86_64/./lib/home/xavier/.local/share/Steam/SteamApps/common/rust/rust_Data/Plugins/x86/libSteamNative.so
Fallback handler could not load library /home/xavier/.local/share/Steam/SteamApps/common/rust/rust_Data/Mono/x86_64/lib/home/xavier/.local/share/Steam/SteamApps/common/rust/rust_Data/Plugins/x86/libSteamNative.so
I made a symbolic link of /home in "rust_Data/Mono/x86_64" in such a way that /home/xavier/.local/share/Steam/SteamApps/common/rust/rust_Data/Mono/x86_64/.//home/xavier/.local/share/Steam/SteamApps/common/rust/rust_Data/Plugins/x86/libSteamNative.so would exist but is still not loaded by rust :(