Sometimes you want to open local game data or the AppData Folder, which is not that easily to find on SteamOS, as you are using Wine/Proton to play those Windows Games on Linux.
Heres a example how Proton organizes those directories (here it is a example of Last Epochs AppData-Folder):
/home/deck/.local/share/Steam/steamapps/compatdata/899770/pfx/drive_c/users/steamuser/AppData/LocalLow/Eleventh Hour Games/Last Epoch/Filters
is the path for the equivalent of the following Path in Windows.
C:\Users\USERNAME\AppData\LocalLow\Eleventh Hour Games\Last Epoch\Filters
So you need to go to
If you dont know what ID your game has, you can checkup the steam-game ids on this website: https://steamdb.info/apps/