Also on Gentoo here. Ephinea has been running on Linux for years. I tested installing it in a new Wine prefix(Wine 7.0.1) just now and ran into zero issues. Loaded into lobby and then Episoda 2 Seaside with no lag or sound issues(on Pulseaudio). Both mods and graphics fixes(dgVoodoo) will work...
Running game on Linux here (Gentoo, wine-vanilla 7.0). Recent update broke online.exe. I completely wiped my PSO wine prefix and used Winetricks to install dotnet462 and the game now works.
Specifically I ran this command "winetricks --force dotnet462 corefonts"
en4cer, Wineskin has...
It's a combo of an old version of Wine plus Steam. Try deleting /dev/input/js0 and js1 if present. This is safe, they're device files which are auto generated on modern Linux. I could yap to explain but not important.