This game is currently the only game I can't play with my friends on Linux and have to boot to Windows.
Most games I play run the Windows version via proton, but because HFF "supports" Linux natively by having a Linux depot and a launch configuration, steam uses that instead.
The Linux version is outdated and last updated 6.3 years ago according to steamdb, and I cannot connect to multiplayer lobbies in that version.
Please consider updating the linux version, or completely remove it to make steam launch the latest Windows version with proton.