you can change the settings manually as a workaround:
step 1: C:\Users\yourusername\AppData\Local\SquidGame\Saved\Config\Windows
step 2: open the file GameUserSettings.ini with text editor
step 3: change sg. values from 3 to 2 or 1 and save the file
3=high quality
2=medium
1=low
step 4: start the game and now the quality is lower = higher fps