Like the tittle says, I can´t change this options in particular

Yes, resolution eems fixed, but fps cap is under the graphics optins.

If you're still experiencing this issue, try changing the Graphics settings to what you want, select "Back," select "Audio," and select "Back." At the moment it's bugged and the only way to get the game to save your settings from the main menu is to go into the Audio settings and back out.