Game shape dude, game shape.
Your highest salaried player has played 123 minutes this week. Thats double what he should be playing. I didn't check the amount of minutes of the rest, I didn't have to. Their game shape tells me instantly you're mis-managing minutes.
Get all of your (decent) players playing 60-65 minutes a week, you'll see a marked improvement in their performance once they get back to strong/proficient GS like they should be.